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/common/qixis.c b/board/freescale/common/qixis.c
index 2b74d02..40ce6b0 100644
--- a/board/freescale/common/qixis.c
+++ b/board/freescale/common/qixis.c
@@ -2,13 +2,9 @@
  * Copyright 2011 Freescale Semiconductor
  * Author: Shengzhou Liu <Shengzhou.Liu@freescale.com>
  *
- * 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+
  *
  * This file provides support for the QIXIS of some Freescale reference boards.
- *
  */
 
 #include <common.h>