Add GPL-2.0+ SPDX-License-Identifier to source files

Signed-off-by: Wolfgang Denk <wd@denx.de>
[trini: Fixup common/cmd_io.c]
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/board/a3m071/mt46v16m16-75.h b/board/a3m071/mt46v16m16-75.h
index e49e996..8f42830 100644
--- a/board/a3m071/mt46v16m16-75.h
+++ b/board/a3m071/mt46v16m16-75.h
@@ -2,18 +2,7 @@
  * (C) Copyright 2004
  * Mark Jonas, Freescale Semiconductor, mark.jonas@motorola.com.
  *
- * See file CREDITS for list of people who contributed to this
- * project.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
+ * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #define SDRAM_DDR		/* is DDR */