fix(cpus): workaround for Neoverse-N3 erratum 3699563

Neoverse-N3 erratum 3699563 that applies to r0p0 is still Open.

The workaround is for EL3 software that performs context save/restore
on a change of Security state to use a value of SCR_EL3.NS when
accessing ICH_VMCR_EL2 that reflects the Security state that owns the
data being saved or restored.

SDEN documentation:
https://developer.arm.com/documentation/SDEN-3050973/latest/

Change-Id: I77aaf8ae0afff3adde9a85f4a1a13ac9d1daf0af
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index abe4699..be4ce77 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -733,6 +733,11 @@
 # of the Neoverse N2 cpu and is still open.
 CPU_FLAG_LIST += ERRATA_N2_3701773
 
+# Flag to apply erratum 3699563 workaround during context save/restore of
+# ICH_VMCR_EL2 reg. This erratum applies to revision r0p0 of the Neoverse N3
+# cpu and is still open.
+CPU_FLAG_LIST += ERRATA_N3_3699563
+
 # Flag to apply erratum 2002765 workaround during reset. This erratum applies
 # to revisions r0p0, r1p0, and r2p0 of the Cortex-X2 cpu and is still open.
 CPU_FLAG_LIST += ERRATA_X2_2002765