Tegra: platform specific GIC sources

The TEGRA_GICv2_SOURCES contains the list of GIC sources required
to compile the GICv2 support for platforms.

This patch includes the TEGRA_GICv2_SOURCES macro from individual
makefiles to allow future platforms to use suport for GICv3.

Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Change-Id: I429b1a0c7764ab370675f873a50cecda871110cb
diff --git a/plat/nvidia/tegra/soc/t186/platform_t186.mk b/plat/nvidia/tegra/soc/t186/platform_t186.mk
index 6739c50..5275b8e 100644
--- a/plat/nvidia/tegra/soc/t186/platform_t186.mk
+++ b/plat/nvidia/tegra/soc/t186/platform_t186.mk
@@ -40,7 +40,8 @@
 PLAT_INCLUDES		+=	-Iplat/nvidia/tegra/include/t186 \
 				-I${SOC_DIR}/drivers/include
 
-BL31_SOURCES		+=	drivers/ti/uart/aarch64/16550_console.S	\
+BL31_SOURCES		+=	${TEGRA_GICv2_SOURCES}			\
+				drivers/ti/uart/aarch64/16550_console.S	\
 				lib/cpus/aarch64/denver.S		\
 				lib/cpus/aarch64/cortex_a57.S		\
 				${TEGRA_DRIVERS}/bpmp_ipc/intf.c	\