Common: Relicense TypeUtils to CC0

I am the sole contributor (apart from e149ad4f0a which only changed the license header).

Source/Core/Common/TypeUtils.h

@@ -1,5 +1,4 @@
-// Copyright 2021 Dolphin Emulator Project
-// SPDX-License-Identifier: GPL-2.0-or-later
+// SPDX-License-Identifier: CC0-1.0
 
 #pragma once