nds32: Update <asm/io.h> and <asm/setup.h> with SPDX license identifiers

Signed-off-by: NTom Rini <trini@ti.com>

arch/nds32/include/asm/io.h

@@ -7,9 +7,7 @@
  * Shawn Lin, Andes Technology Corporation <nobuhiro@andestech.com>
  * Macpaul Lin, Andes Technology Corporation <macpaul@andestech.com>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
+ * SPDX-License-Identifier:	GPL-2.0
  *
  * Modifications:
  *  16-Sep-1996	RMK	Inlined the inx/outx functions & optimised for both

arch/nds32/include/asm/setup.h

@@ -5,9 +5,7 @@
  *  Copyright (C) 2008 Andes Technology Corporation
  *	Copyright (C) 2013 Ken Kuo (ken_kuo@andestech.com)
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
+ * SPDX-License-Identifier:	GPL-2.0
  *
  *  Structure passed to kernel to tell it about the
  *  hardware it's running on.  See Documentation/arm/Setup