Cortex-A72: Implement workaround for erratum 859971

Erratum 855971 applies to revision r0p3 or earlier Cortex-A72 CPUs. The
recommended workaround is to disable instruction prefetch.

Change-Id: I7fde74ee2a8a23b2a8a1891b260f0eb909fad4bf
Signed-off-by: Eleanor Bonnici <Eleanor.bonnici@arm.com>
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 198a32e3..31adfb4 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -95,6 +95,10 @@
 # only to revision <= r1p3 of the Cortex A57 cpu.
 ERRATA_A57_859972	?=0
 
+# Flag to apply erratum 855971 workaround during reset. This erratum applies
+# only to revision <= r0p3 of the Cortex A72 cpu.
+ERRATA_A72_859971	?=0
+
 # Process ERRATA_A53_826319 flag
 $(eval $(call assert_boolean,ERRATA_A53_826319))
 $(eval $(call add_define,ERRATA_A53_826319))
@@ -151,6 +155,10 @@
 $(eval $(call assert_boolean,ERRATA_A57_859972))
 $(eval $(call add_define,ERRATA_A57_859972))
 
+# Process ERRATA_A72_859971 flag
+$(eval $(call assert_boolean,ERRATA_A72_859971))
+$(eval $(call add_define,ERRATA_A72_859971))
+
 # Errata build flags
 ifneq (${ERRATA_A53_843419},0)
 TF_LDFLAGS_aarch64	+= --fix-cortex-a53-843419