chore: make yuzu REUSE compliant

[REUSE] is a specification that aims at making file copyright
information consistent, so that it can be both human and machine
readable. It basically requires that all files have a header containing
copyright and licensing information. When this isn't possible, like
when dealing with binary assets, generated files or embedded third-party
dependencies, it is permitted to insert copyright information in the
`.reuse/dep5` file.

Oh, and it also requires that all the licenses used in the project are
present in the `LICENSES` folder, that's why the diff is so huge.
This can be done automatically with `reuse download --all`.

The `reuse` tool also contains a handy subcommand that analyzes the
project and tells whether or not the project is (still) compliant,
`reuse lint`.

Following REUSE has a few advantages over the current approach:

- Copyright information is easy to access for users / downstream
- Files like `dist/license.md` do not need to exist anymore, as
  `.reuse/dep5` is used instead
- `reuse lint` makes it easy to ensure that copyright information of
  files like binary assets / images is always accurate and up to date

To add copyright information of files that didn't have it I looked up
who committed what and when, for each file. As yuzu contributors do not
have to sign a CLA or similar I couldn't assume that copyright ownership
was of the "yuzu Emulator Project", so I used the name and/or email of
the commit author instead.

[REUSE]: https://reuse.software

Follow-up to 01cf05bc75b1e47beb08937439f3ed9339e7b254

9 files changed, 18 insertions, 27 deletions

diff --git a/src/core/hle/ipc.h b/src/core/hle/ipc.h
index 602e12606..416da15ec 100644
--- a/src/core/hle/ipc.h
+++ b/src/core/hle/ipc.h
@@ -1,6 +1,5 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2016 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/ipc_helpers.h b/src/core/hle/ipc_helpers.h
index 004bb2005..d631c0357 100644
--- a/src/core/hle/ipc_helpers.h
+++ b/src/core/hle/ipc_helpers.h
@@ -1,6 +1,5 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2016 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/kernel/k_client_port.cpp b/src/core/hle/kernel/k_client_port.cpp
index d63e77d15..3cb22ff4d 100644
--- a/src/core/hle/kernel/k_client_port.cpp
+++ b/src/core/hle/kernel/k_client_port.cpp
@@ -1,6 +1,5 @@
-// Copyright 2021 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2021 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "common/scope_exit.h"
 #include "core/hle/kernel/hle_ipc.h"
diff --git a/src/core/hle/kernel/k_client_port.h b/src/core/hle/kernel/k_client_port.h
index ef8583efc..e17eff28f 100644
--- a/src/core/hle/kernel/k_client_port.h
+++ b/src/core/hle/kernel/k_client_port.h
@@ -1,6 +1,5 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2016 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/kernel/k_process.cpp b/src/core/hle/kernel/k_process.cpp
index b662788b3..d3e99665f 100644
--- a/src/core/hle/kernel/k_process.cpp
+++ b/src/core/hle/kernel/k_process.cpp
@@ -1,6 +1,5 @@
-// Copyright 2015 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2015 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <algorithm>
 #include <bitset>
diff --git a/src/core/hle/kernel/k_process.h b/src/core/hle/kernel/k_process.h
index 5e3e22ad8..d56d73bab 100644
--- a/src/core/hle/kernel/k_process.h
+++ b/src/core/hle/kernel/k_process.h
@@ -1,6 +1,5 @@
-// Copyright 2015 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2015 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/kernel/k_shared_memory.cpp b/src/core/hle/kernel/k_shared_memory.cpp
index b77735736..8ff1545b6 100644
--- a/src/core/hle/kernel/k_shared_memory.cpp
+++ b/src/core/hle/kernel/k_shared_memory.cpp
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "common/assert.h"
 #include "core/core.h"
diff --git a/src/core/hle/kernel/k_shared_memory.h b/src/core/hle/kernel/k_shared_memory.h
index 2c1db0e70..34cb98456 100644
--- a/src/core/hle/kernel/k_shared_memory.h
+++ b/src/core/hle/kernel/k_shared_memory.h
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/result.h b/src/core/hle/result.h
index aa9e5b89d..4de44cd06 100644
--- a/src/core/hle/result.h
+++ b/src/core/hle/result.h
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once