TF-A GICv3 driver: Separate GICD and GICR accessor functions

This patch provides separation of GICD, GICR accessor
functions and adds new macros for GICv3 registers access
as a preparation for GICv3.1 and GICv4 support.
NOTE: Platforms need to modify to include both
'gicdv3_helpers.c' and 'gicrv3_helpers.c' instead of the
single helper file previously.

Change-Id: I1641bd6d217d6eb7d1228be3c4177b2d556da60a
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
diff --git a/plat/arm/board/fvp/platform.mk b/plat/arm/board/fvp/platform.mk
index 05c11ce..c32b302 100644
--- a/plat/arm/board/fvp/platform.mk
+++ b/plat/arm/board/fvp/platform.mk
@@ -56,6 +56,8 @@
 FVP_GICV3_SOURCES	:=	drivers/arm/gic/common/gic_common.c	\
 				drivers/arm/gic/v3/gicv3_main.c		\
 				drivers/arm/gic/v3/gicv3_helpers.c	\
+				drivers/arm/gic/v3/gicdv3_helpers.c	\
+				drivers/arm/gic/v3/gicrv3_helpers.c	\
 				plat/common/plat_gicv3.c		\
 				plat/arm/common/arm_gicv3.c