feat(tc): enable trbe errata flags for Cortex-A520 and X4

Enable following erratas as per the TARGET_PLATFORM of TC
 - ERRATA_A520_2938996
 - ERRATA_X4_2726228

Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: Ia552473740c34867dd9fd619faf378adcb784821
diff --git a/plat/arm/board/tc/platform.mk b/plat/arm/board/tc/platform.mk
index f3c3b4c..1a7289a 100644
--- a/plat/arm/board/tc/platform.mk
+++ b/plat/arm/board/tc/platform.mk
@@ -110,6 +110,9 @@
 
 # CPU libraries for TARGET_PLATFORM=2
 ifeq (${TARGET_PLATFORM}, 2)
+ERRATA_A520_2938996	:=	1
+ERRATA_X4_2726228	:=	1
+
 TC_CPU_SOURCES	+=	lib/cpus/aarch64/cortex_a520.S \
 			lib/cpus/aarch64/cortex_a720.S \
 			lib/cpus/aarch64/cortex_x4.S
@@ -117,6 +120,8 @@
 
 # CPU libraries for TARGET_PLATFORM=3
 ifeq (${TARGET_PLATFORM}, 3)
+ERRATA_A520_2938996	:=	1
+
 TC_CPU_SOURCES	+=	lib/cpus/aarch64/cortex_a520.S \
 			lib/cpus/aarch64/cortex_a725.S \
 			lib/cpus/aarch64/cortex_x925.S