Fix cortex-a53 inclusion of files.

I accidentally broken the cortex-a53 because it directly includes files
from cortex-a15. Rather than revert that part, just copy over the files
that are needed directly so we don't run into this in the future.

Test: Built the aosp_angler-userdebug target using cortex-a53 as the
Test: arm target. Then built the bionic unit tests and ran them on
Test: an angler.

Change-Id: Id89e240b31f94e99f5076e1de973a9344486ec35