Add more SPDX-License-Identifier tags

In a number of places we had wordings of the GPL (or LGPL in a few
cases) license text that were split in such a way that it wasn't caught
previously.  Convert all of these to the correct SPDX-License-Identifier
tag.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-bcm283x/lowlevel_init.S b/arch/arm/mach-bcm283x/lowlevel_init.S
index c7b0843..965de1d 100644
--- a/arch/arm/mach-bcm283x/lowlevel_init.S
+++ b/arch/arm/mach-bcm283x/lowlevel_init.S
@@ -4,14 +4,7 @@
  * 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.
- *
- * 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
  */
 
 .globl lowlevel_init