Revert "Use aarch64-linux-android-4.9 for arm64 build (attempt #2)"

This reverts commit 1ae9b213eb5648205223e4b825f4c808a5d2ace8.
Sigh... new warnings found by 4.9 break checkbuild.

Change-Id: I46ad622fa9c8ac4fb1e15e29bb400634abc5914c
1 file changed