SplitUVRow_AVX2 ported to GCC/NaCL. BUG=269 TESTED=validator for nacl. R=harryjin@google.com
SplitUVRow_AVX2 ported to GCC/NaCL.
BUG=269
TESTED=validator for nacl.
R=harryjin@google.com

Review URL: https://webrtc-codereview.appspot.com/28979004

git-svn-id: a51711482b6ba0e1d1ab095578a045eeae45ac9a@1156 16f28f9a-4ce2-e073-06de-1de4eb20be90

xlncz/libyuv,lyx2014/yuv,disigma/yuv,lyx2014/libyuv_free,PeterXu/libyuv,disigma/yuv,lyx2014/yuv,Bilibili/libyuv,yarrcc/libyuv-ios,xlncz/libyuv,Bilibili/libyuv,godghdai/libyuv,xlncz/libyuv,labdong801/libyuv,jpxiong/libyuv,PeterXu/libyuv,lyx2014/libyuv_free,openpeer/libyuv,xlncz/libyuv,yarrcc/libyuv-ios,lyx2014/libyuv_free,okumura/libyuv,jpxiong/libyuv,yarrcc/libyuv-ios,lemenkov/libyuv,jpxiong/libyuv,lemenkov/libyuv,godghdai/libyuv,lyx2014/yuv,openpeer/libyuv,okumura/libyuv,yarrcc/libyuv-ios,godghdai/libyuv,labdong801/libyuv,openpeer/libyuv,Bilibili/libyuv,PeterXu/libyuv,okumura/libyuv,disigma/yuv,lyx2014/libyuv_free,lyx2014/yuv,lemenkov/libyuv,lemenkov/libyuv,labdong801/libyuv