TF-A GICv2 driver: Introduce makefile

This patch moves all GICv2 driver files into new added
'gicv2.mk' makefile for the benefit of the generic driver
which can evolve in the future without affecting platforms.

NOTE: Usage of 'drivers/arm/gic/common/gic_common.c' file
is now deprecated and platforms with GICv2 driver need to
be modified to include 'drivers/arm/gic/v2/gicv2.mk' in
their makefiles.

Change-Id: Ib10e71bdda0e5c7e80a049ddce2de1dd839602d1
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
diff --git a/drivers/arm/gic/v2/gicv2.mk b/drivers/arm/gic/v2/gicv2.mk
new file mode 100644
index 0000000..49996bb
--- /dev/null
+++ b/drivers/arm/gic/v2/gicv2.mk
@@ -0,0 +1,15 @@
+#
+# Copyright (c) 2020, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+# No support for extended PPI and SPI range
+GIC_EXT_INTID	:=	0
+
+GICV2_SOURCES	+=	drivers/arm/gic/v2/gicv2_main.c		\
+			drivers/arm/gic/v2/gicv2_helpers.c	\
+			drivers/arm/gic/v2/gicdv2_helpers.c
+
+# Set GICv2 build option
+$(eval $(call add_define,GIC_EXT_INTID))
\ No newline at end of file