css: Do not map the non-secure RAM as secure

Change-Id: I7e73c0ab134da11c49f990b739245110c59eac2b
Signed-off-by: Chris Kay <chris.kay@arm.com>

include/plat/arm/css/common/css_def.h

@@ -99,7 +99,7 @@
 #define CSS_MAP_NSRAM			MAP_REGION_FLAT(		\
 						NSRAM_BASE,	\
 						NSRAM_SIZE,	\
-						MT_DEVICE | MT_RW | MT_SECURE)
+						MT_DEVICE | MT_RW | MT_NS)
 
 /* Platform ID address */
 #define SSC_VERSION_OFFSET			0x040