Fix build for SEPARATE_CODE_AND_RODATA=0

TF won't build since no memory region is specified
for when SEPARATE_CODE_AND_RODATA=0 it still relies on
the ARM_MAP_BL_RO_DATA region which is never defined for
this case. Create memory region combining code and RO data for
when the build flag SEPARATE_CODE_AND_RODATA=0 to fix this

Change-Id: I6c129eb0833497710cce55e76b8908ce03e0a638
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
diff --git a/plat/arm/common/arm_bl31_setup.c b/plat/arm/common/arm_bl31_setup.c
index 557854c..0b64804 100644
--- a/plat/arm/common/arm_bl31_setup.c
+++ b/plat/arm/common/arm_bl31_setup.c
@@ -287,8 +287,7 @@
 
 	const mmap_region_t bl_regions[] = {
 		MAP_BL31_TOTAL,
-		ARM_MAP_BL_CODE,
-		ARM_MAP_BL_RO_DATA,
+		ARM_MAP_BL_RO,
 #if USE_COHERENT_MEM
 		ARM_MAP_BL_COHERENT_RAM,
 #endif