feat(mte): add mte2 feat

Add support for feat mte2. tfsr_el2 is available only with mte2,
however currently its context_save/restore is done with mte rather than
mte2, so introduce 'is_feat_mte2_supported' to check mte2.

Change-Id: I108d9989a8f5b4d1d2f3b9865a914056fa566cf2
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
diff --git a/make_helpers/arch_features.mk b/make_helpers/arch_features.mk
index a346dac..643d550 100644
--- a/make_helpers/arch_features.mk
+++ b/make_helpers/arch_features.mk
@@ -319,6 +319,15 @@
         endif
 endif
 ENABLE_FEAT_MTE		                ?=	0
+ENABLE_FEAT_MTE2		        ?=	0
+
+
+# Add a error message to indicate incorrect MTE2 selection without MTE enabled.
+ifneq ($(ENABLE_FEAT_MTE2),0)
+        ifeq ($(ENABLE_FEAT_MTE),0)
+               $(error ENABLE_FEAT_MTE2 is not supported without enabling ENABLE_FEAT_MTE)
+        endif
+endif
 
 #----
 # 8.6