Neoverse N1: Introduce workaround for Neoverse N1 erratum 1315703

Neoverse N1 erratum 1315703 is a Cat A (rare) erratum [1], present in
older revisions of the Neoverse N1 processor core.
The workaround is to set a bit in the implementation defined CPUACTLR2_EL1
system register, which will disable the load-bypass-store feature.

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.pjdocpjdoc-466751330-1032/index.html

Change-Id: I5c708dbe0efa4daa0bcb6bd9622c5efe19c03af9
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 599e11e..db45375 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -238,6 +238,10 @@
 # only to r0p0 and r1p0 of the Neoverse N1 cpu.
 ERRATA_N1_1043202	?=1
 
+# Flag to apply erratum 1315703 workaround during reset. This erratum applies
+# to revisions before r3p1 of the Neoverse N1 cpu.
+ERRATA_N1_1315703	?=1
+
 # 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
@@ -427,6 +431,10 @@
 $(eval $(call assert_boolean,ERRATA_N1_1043202))
 $(eval $(call add_define,ERRATA_N1_1043202))
 
+# Process ERRATA_N1_1315703 flag
+$(eval $(call assert_boolean,ERRATA_N1_1315703))
+$(eval $(call add_define,ERRATA_N1_1315703))
+
 # Process ERRATA_DSU_798953 flag
 $(eval $(call assert_boolean,ERRATA_DSU_798953))
 $(eval $(call add_define,ERRATA_DSU_798953))