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/include/configs/hawkboard.h b/include/configs/hawkboard.h
index 8d27590..2e478cc 100644
--- a/include/configs/hawkboard.h
+++ b/include/configs/hawkboard.h
@@ -5,19 +5,7 @@
  *
  * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
  *
- * 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+
  */
 
 #ifndef __CONFIG_H