Add missing features to the Tegra GIC driver

In order to handle secure/non-secure interrupts, overload the plat_ic_*
functions and copy GIC helper functions from arm_gic.c. Use arm_gic.c
as the reference to add Tegra's GIC helper functions.

Now that Tegra has its own GIC implementation, we have no use for
plat_gic.c and arm_gic.c files.

Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
diff --git a/plat/nvidia/tegra/common/tegra_common.mk b/plat/nvidia/tegra/common/tegra_common.mk
index 12d684f..73e1281 100644
--- a/plat/nvidia/tegra/common/tegra_common.mk
+++ b/plat/nvidia/tegra/common/tegra_common.mk
@@ -43,14 +43,12 @@
 
 COMMON_DIR		:=	plat/nvidia/tegra/common
 
-BL31_SOURCES		+=	drivers/arm/gic/arm_gic.c			\
-				drivers/arm/gic/gic_v2.c			\
+BL31_SOURCES		+=	drivers/arm/gic/gic_v2.c			\
 				drivers/arm/gic/gic_v3.c			\
 				drivers/console/console.S			\
 				drivers/ti/uart/16550_console.S			\
 				lib/cpus/aarch64/cortex_a53.S			\
 				lib/cpus/aarch64/cortex_a57.S			\
-				plat/common/plat_gic.c				\
 				plat/common/aarch64/platform_mp_stack.S		\
 				${COMMON_DIR}/aarch64/tegra_helpers.S		\
 				${COMMON_DIR}/drivers/memctrl/memctrl.c		\