feat(plat/arm/sgi) increase memory reserved for bl31 image

Increase the size of bl31 image by 52K to accomodate increased size of
xlat table.
Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Change-Id: Ic3a8d8be1104adf48d22aa829e2197f710b6b666

plat/arm/css/sgi/include/sgi_base_platform_def.h

@@ -98,7 +98,7 @@
  * calculated using the current BL31 PROGBITS debug size plus the sizes of
  * BL2 and BL1-RW
  */
-#define PLAT_ARM_MAX_BL31_SIZE		0x3B000
+#define PLAT_ARM_MAX_BL31_SIZE		0x48000
 
 /*
  * Size of cacheable stacks