libgo: fix build on AIX

Since aix/ppc64 has been added to GC toolchain, a mix between new and
old files were created in gcc toolchain.
This commit corrects this merge for aix/ppc64 and aix/ppc.

Change-Id: I237ed6a3671996dce47163bd8afe7d6c6d7efb48
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/167658
Reviewed-by: Ian Lance Taylor <iant@golang.org>
28 files changed