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/lib/_ashrdi3.S b/arch/arm/lib/_ashrdi3.S
index 671ac87..4d93c8a 100644
--- a/arch/arm/lib/_ashrdi3.S
+++ b/arch/arm/lib/_ashrdi3.S
@@ -1,30 +1,8 @@
 /* Copyright 1995, 1996, 1998, 1999, 2000, 2003, 2004, 2005
    Free Software Foundation, Inc.
 
-This file 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, or (at your option) any
-later version.
-
-In addition to the permissions in the GNU General Public License, the
-Free Software Foundation gives you unlimited permission to link the
-compiled version of this file into combinations with other programs,
-and to distribute those combinations without any restriction coming
-from the use of this file.  (The General Public License restrictions
-do apply in other respects; for example, they cover modification of
-the file, and distribution when not linked into a combine
-executable.)
-
-This file 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; see the file COPYING.  If not, write to
-the Free Software Foundation, 51 Franklin Street, Fifth Floor,
-Boston, MA 02110-1301, USA.  */
-
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
 
 #ifdef __ARMEB__
 #define al r1