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/freescale/mpc837xemds/mpc837xemds.c b/board/freescale/mpc837xemds/mpc837xemds.c
index 650a4fe..0a3c972 100644
--- a/board/freescale/mpc837xemds/mpc837xemds.c
+++ b/board/freescale/mpc837xemds/mpc837xemds.c
@@ -2,12 +2,7 @@
  * Copyright (C) 2007,2010 Freescale Semiconductor, Inc.
  * Dave Liu <daveliu@freescale.com>
  *
- * CREDITS: Kim Phillips contribute to LIBFDT code
- *
- * 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.
+ * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <common.h>