feat(debugv8p9): add support for FEAT_Debugv8p9

This patch enables FEAT_Debugv8p9 and prevents EL1/0 from
trapping to EL3 when accessing MDSELR_EL1 register by
setting the MDCR_EL3.EBWE bit.

Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I3613af1dd8cb8c0d3c33dc959f170846c0b9695a
diff --git a/Makefile b/Makefile
index bbde1a7..cb5eb36 100644
--- a/Makefile
+++ b/Makefile
@@ -1227,6 +1227,7 @@
 	ENABLE_FEAT_AMUv1p1 \
 	ENABLE_FEAT_CSV2_2 \
 	ENABLE_FEAT_CSV2_3 \
+	ENABLE_FEAT_DEBUGV8P9 \
 	ENABLE_FEAT_DIT \
 	ENABLE_FEAT_ECV \
 	ENABLE_FEAT_FGT \
@@ -1297,6 +1298,7 @@
 	AMU_RESTRICT_COUNTERS \
 	ENABLE_ASSERTIONS \
 	ENABLE_BTI \
+	ENABLE_FEAT_DEBUGV8P9 \
 	ENABLE_FEAT_MPAM \
 	ENABLE_PAUTH \
 	ENABLE_PIE \