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/board/iomega/iconnect/kwbimage.cfg b/board/iomega/iconnect/kwbimage.cfg
index 1b66207..3c63a03 100644
--- a/board/iomega/iconnect/kwbimage.cfg
+++ b/board/iomega/iconnect/kwbimage.cfg
@@ -3,21 +3,7 @@
 # Wojciech Dubowik <wojciech.dubowik@neratec.com>
 # Luka Perkov <luka@openwrt.org>
 #
-# 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, see <http://www.gnu.org/licenses/>.
+# SPDX-License-Identifier:	GPL-2.0+
 #
 # Refer doc/README.kwbimage for more details about how-to configure
 # and create kirkwood boot image