Add cortex-a53 as a valid instruction set variant for arm64.

Change-Id: I720e2cc4acd94e367dae4a21c13aa90a3e30b7cc
diff --git a/runtime/arch/arm64/instruction_set_features_arm64.cc b/runtime/arch/arm64/instruction_set_features_arm64.cc
index 1f2ce02..395cee8 100644
--- a/runtime/arch/arm64/instruction_set_features_arm64.cc
+++ b/runtime/arch/arm64/instruction_set_features_arm64.cc
@@ -30,7 +30,7 @@
 
   // Look for variants that need a fix for a53 erratum 835769.
   static const char* arm64_variants_with_a53_835769_bug[] = {
-      "default", "generic"  // Pessimistically assume all generic ARM64s are A53s.
+      "default", "generic", "cortex-a53"  // Pessimistically assume all generic ARM64s are A53s.
   };
   bool needs_a53_835769_fix = FindVariantInArray(arm64_variants_with_a53_835769_bug,
                                                  arraysize(arm64_variants_with_a53_835769_bug),