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/drivers/net/ep93xx_eth.c b/drivers/net/ep93xx_eth.c
index 245ad1c..1c09f10 100644
--- a/drivers/net/ep93xx_eth.c
+++ b/drivers/net/ep93xx_eth.c
@@ -14,21 +14,7 @@
  * Adam Bezanson, Network Audio Technologies, Inc.
  * <bezanson@netaudiotech.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.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 675 Mass Ave, Cambridge, MA 02139, USA.
+ * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <command.h>