treewide: convert GPLv2+ license info to SPDX tags

SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.

Source/Core/Core/DSP/Interpreter/DSPIntArithmetic.cpp

@@ -1,6 +1,5 @@
 // Copyright 2009 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 //
 // Additional copyrights go to Duddie and Tratax (c) 2004
 

Source/Core/Core/DSP/Interpreter/DSPIntBranch.cpp

@@ -1,6 +1,5 @@
 // Copyright 2009 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 //
 // Additional copyrights go to Duddie and Tratax (c) 2004
 

Source/Core/Core/DSP/Interpreter/DSPIntCCUtil.h

@@ -1,6 +1,5 @@
 // Copyright 2008 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 //
 // Additional copyrights go to Duddie and Tratax (c) 2004
 

Source/Core/Core/DSP/Interpreter/DSPIntExtOps.cpp

@@ -1,6 +1,5 @@
 // Copyright 2009 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "Core/DSP/Interpreter/DSPInterpreter.h"
 

Source/Core/Core/DSP/Interpreter/DSPIntLoadStore.cpp

@@ -1,6 +1,5 @@
 // Copyright 2009 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 //
 // Additional copyrights go to Duddie and Tratax (c) 2004
 

Source/Core/Core/DSP/Interpreter/DSPIntMisc.cpp

@@ -1,6 +1,5 @@
 // Copyright 2009 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 //
 // Additional copyrights go to Duddie and Tratax (c) 2004
 

Source/Core/Core/DSP/Interpreter/DSPIntMultiplier.cpp

@@ -1,6 +1,5 @@
 // Copyright 2009 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 //
 // Additional copyrights go to Duddie and Tratax (c) 2004
 

Source/Core/Core/DSP/Interpreter/DSPIntTables.cpp

@@ -1,6 +1,5 @@
 // Copyright 2018 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "Core/DSP/Interpreter/DSPIntTables.h"
 

Source/Core/Core/DSP/Interpreter/DSPIntTables.h

@@ -1,6 +1,5 @@
 // Copyright 2018 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 

Source/Core/Core/DSP/Interpreter/DSPIntUtil.h

@@ -1,7 +1,6 @@
 // Copyright 2008 Dolphin Emulator Project
 // Copyright 2005 Duddie
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 

Source/Core/Core/DSP/Interpreter/DSPInterpreter.cpp

@@ -1,7 +1,6 @@
 // Copyright 2008 Dolphin Emulator Project
 // Copyright 2004 Duddie & Tratax
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "Core/DSP/Interpreter/DSPInterpreter.h"
 

Source/Core/Core/DSP/Interpreter/DSPInterpreter.h

@@ -1,6 +1,5 @@
 // Copyright 2009 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once