Correct License and Copyright information on few files

gpio.h - Added missing copyright in few files.
rsa-mod-exp.h - Corrected copyright in the file.
fsl_sec.h - Added missing license in files
drivers/crypto/fsl/Makefile - Removed the incomplete GPLv2 license and replaced it with GPLv2+ license

Signed-off-by: Ruchika Gupta <ruchika.gupta@freescale.com>
diff --git a/drivers/crypto/fsl/Makefile b/drivers/crypto/fsl/Makefile
index 4aa91e4..fd736cf 100644
--- a/drivers/crypto/fsl/Makefile
+++ b/drivers/crypto/fsl/Makefile
@@ -1,9 +1,7 @@
 #
 # Copyright 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+
 #
 
 obj-y += sec.o