bcm2835/rpi: add SPDX license tags for some files

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
diff --git a/board/raspberrypi/rpi/Makefile b/board/raspberrypi/rpi/Makefile
index c53c92b..4ce2c98 100644
--- a/board/raspberrypi/rpi/Makefile
+++ b/board/raspberrypi/rpi/Makefile
@@ -1,15 +1,7 @@
 #
-# 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
-# version 2 as published by the Free Software Foundation.
+# (C) Copyright 2012 Stephen Warren
 #
-# 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.
+# SPDX-License-Identifier:	GPL-2.0
 #
 
 obj-y	:= rpi.o