Follow-up for r291277: Add a return to silence GCC's "control reaches end of non-void function" warning.

llvm-svn: 291639

compiler-rt/lib/sanitizer_common/sanitizer_common.h

@@ -690,6 +690,7 @@ inline const char *ModuleArchToString(ModuleArch arch) {
       return "arm64";
   }
   CHECK(0 && "Invalid module arch");
+  return "";
 }
 
 const uptr kModuleUUIDSize = 16;