BUG=none
TESTED=libyuv unittests all pass with AVX2
R=tpsiaki@google.com

Review URL: https://webrtc-codereview.appspot.com/44999004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1358 16f28f9a-4ce2-e073-06de-1de4eb20be90