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/board/freescale/mpc8555cds/ddr.c b/board/freescale/mpc8555cds/ddr.c
index d2ac6c4..e438737 100644
--- a/board/freescale/mpc8555cds/ddr.c
+++ b/board/freescale/mpc8555cds/ddr.c
@@ -1,9 +1,7 @@
 /*
  * Copyright 2008 Freescale Semiconductor, Inc.
  *
- * 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.
+ * SPDX-License-Identifier:	GPL-2.0
  */
 
 #include <common.h>