ref: 303f144eefc739c44a3e18a24f8cf61d2fe103a7
parent: 16a4fab9e2c6d80c08183bf0cc27a3e0b9bd2346
author: jackychen <jackychen@google.com>
date: Thu Dec 3 10:21:36 EST 2015
Add vp9_avg_4x4_neon and the unit test. Change-Id: I3ef9a9648841374ed3cc865a02053c14ad821a20