fix(errata): add Cortex-A520 definitions

Include the missing Cortex-A520 header.

Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I45153a1aa2d6dace38650268a32106f5201f48bd
diff --git a/services/std_svc/errata_abi/cpu_errata_info.h b/services/std_svc/errata_abi/cpu_errata_info.h
index e24a621..02dd3a8 100644
--- a/services/std_svc/errata_abi/cpu_errata_info.h
+++ b/services/std_svc/errata_abi/cpu_errata_info.h
@@ -13,6 +13,7 @@
 #if __aarch64__
 #include <cortex_a35.h>
 #include <cortex_a510.h>
+#include <cortex_a520.h>
 #include <cortex_a53.h>
 #include <cortex_a57.h>
 #include <cortex_a55.h>