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/power/twl4030.c b/drivers/power/twl4030.c
index 6610f78..3e50310 100644
--- a/drivers/power/twl4030.c
+++ b/drivers/power/twl4030.c
@@ -2,20 +2,7 @@
  * Copyright (c) 2009 Wind River Systems, Inc.
  * Tom Rix <Tom.Rix at windriver.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.
- *
- * 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., 59 Temple Place, Suite 330, Boston,
- * MA 02111-1307 USA
+ * SPDX-License-Identifier:	GPL-2.0+
  *
  * twl4030_power_reset_init is derived from code on omapzoom,
  * git://git.omapzoom.com/repo/u-boot.git
@@ -34,7 +21,6 @@
  * Derived from Beagle Board and 3430 SDP code by
  *	Richard Woodruff <r-woodruff2 at ti.com>
  *	Syed Mohammed Khasim <khasim at ti.com>
- *
  */
 
 #include <twl4030.h>