RAS: SGI: Add flags needed to build components for RAS feature

Add the various flags that are required to build the components needed
to enable the RAS feature on SGI575 platform. By default, all flags
are set to 0, disabling building of all corresponding components.

Change-Id: I7f8536fba895043ef6e397cc33ac9126cb572132
Signed-off-by: Sughosh Ganu <sughosh.ganu@arm.com>

plat/arm/css/sgi/sgi-common.mk

@@ -8,6 +8,16 @@ ENABLE_PLAT_COMPAT		:=	0
 
 CSS_ENT_BASE			:=	plat/arm/css/sgi
 
+RAS_EXTENSION			:=	0
+
+ENABLE_SPM			:=	0
+
+SDEI_SUPPORT			:=	0
+
+EL3_EXCEPTION_HANDLING		:=	0
+
+HANDLE_EA_EL3_FIRST		:=	0
+
 INTERCONNECT_SOURCES	:=	${CSS_ENT_BASE}/sgi_interconnect.c
 
 PLAT_INCLUDES		+=	-I${CSS_ENT_BASE}/include