Don't define AOS_ARCHITECTURE_arm_frc on k8

It really doesn't apply.

Change-Id: I8468552857f859334c5def504905461007cc5148
diff --git a/tools/cpp/toolchain_config.bzl b/tools/cpp/toolchain_config.bzl
index 9b8b9f6..12cbc76 100644
--- a/tools/cpp/toolchain_config.bzl
+++ b/tools/cpp/toolchain_config.bzl
@@ -289,7 +289,6 @@
                                 "-D__STDC_CONSTANT_MACROS",
                                 "-D__STDC_LIMIT_MACROS",
                                 "-D_FILE_OFFSET_BITS=64",
-                                "-DAOS_ARCHITECTURE_arm_frc",
                                 "-U_FORTIFY_SOURCE",
                                 "-D_FORTIFY_SOURCE=1",
                                 "-fstack-protector",