fix(cpus): workaround for Cortex-A510 erratum 2666669

Cortex-A510 erratum 2666669 applies to revisions r1p1 and lower,
and is fixed in r1p2. The errata is mitigated by setting
IMP_CPUACTLR_EL1[38] to 1.

SDEN documentation:
https://developer.arm.com/documentation/SDEN1873351/latest
https://developer.arm.com/documentation/SDEN1873361/latest

Signed-off-by: Akram Ahmad <Akram.Ahmad@arm.com>
Change-Id: Ief27e4a155e43e75f05f2710d0c7bd5da2dec43f
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 8b790bc..ec0d95e 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -674,6 +674,10 @@
 # to revisions r0p0, r0p1, r0p2, r0p3, r1p0, and r1p1. It is fixed in r1p2.
 ERRATA_A510_2371937	?=0
 
+# Flag to apply erratum 2666669 workaround during reset. This erratum applies
+# to revisions r0p0, r0p1, r0p2, r0p3, r1p0, and r1p1. It is fixed in r1p2.
+ERRATA_A510_2666669	?=0
+
 # Flag to apply DSU erratum 798953. This erratum applies to DSUs revision r0p0.
 # Applying the workaround results in higher DSU power consumption on idle.
 ERRATA_DSU_798953	?=0
@@ -1272,7 +1276,11 @@
 $(eval $(call assert_boolean,ERRATA_A510_2371937))
 $(eval $(call add_define,ERRATA_A510_2371937))
 
-# Process ERRATA_DSU_798953 flag
+# Process ERRATA_A510_2666669 flag
+$(eval $(call assert_boolean,ERRATA_A510_2666669))
+$(eval $(call add_define,ERRATA_A510_2666669))
+
+#Process ERRATA_DSU_798953 flag
 $(eval $(call assert_boolean,ERRATA_DSU_798953))
 $(eval $(call add_define,ERRATA_DSU_798953))