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/arch/arm/cpu/armv7/am33xx/config.mk b/arch/arm/cpu/armv7/am33xx/config.mk
index babf0eb..8e3668f 100644
--- a/arch/arm/cpu/armv7/am33xx/config.mk
+++ b/arch/arm/cpu/armv7/am33xx/config.mk
@@ -1,15 +1,7 @@
 #
 # Copyright (C) 2011, Texas Instruments, Incorporated - http://www.ti.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 "as is" WITHOUT ANY WARRANTY of any
-# kind, whether express or implied; 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+
 #
 ifdef CONFIG_SPL_BUILD
 ALL-y	+= $(OBJTREE)/MLO