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/include/fsl_ddr_sdram.h b/include/fsl_ddr_sdram.h
index 4b022d4..9ea8b63 100644
--- a/include/fsl_ddr_sdram.h
+++ b/include/fsl_ddr_sdram.h
@@ -1,9 +1,7 @@
 /*
  * Copyright 2008-2014 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
  */
 
 #ifndef FSL_DDR_MEMCTL_H