feat(mops): enable FEAT_MOPS in EL3 when INIT_UNUSED_NS_EL2=1

FEAT_MOPS, mandatory from Arm v8.8, is typically managed in EL2.
However, in configurations where NS_EL2 is not enabled,
EL3 must set the HCRX_EL2.MSCEn bit to 1 to enable the feature.

This patch ensures FEAT_MOPS is enabled by setting HCRX_EL2.MSCEn to 1.

Change-Id: Ic4960e0cc14a44279156b79ded50de475b3b21c5
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
diff --git a/make_helpers/arch_features.mk b/make_helpers/arch_features.mk
index a1db0b8..3c9e136 100644
--- a/make_helpers/arch_features.mk
+++ b/make_helpers/arch_features.mk
@@ -83,6 +83,7 @@
 
 # Enable the features which are mandatory from ARCH version 8.8 and upwards.
 ifeq "8.8" "$(word 1, $(sort 8.8 $(ARM_ARCH_MAJOR).$(ARM_ARCH_MINOR)))"
+armv8-8-a-feats		:= ENABLE_FEAT_MOPS
 # 8.7 Compliant
 armv8-8-a-feats         += ${armv8-7-a-feats}
 FEAT_LIST               := ${armv8-8-a-feats}
@@ -213,6 +214,14 @@
 ENABLE_FEAT_HCX			?=	0
 
 #----
+# 8.8
+#----
+
+# Flag to enable FEAT_MOPS (Standardization of Memory operations)
+# when INIT_UNUSED_NS_EL2 = 1
+ENABLE_FEAT_MOPS		?=	0
+
+#----
 # 8.9
 #----