Fix for build on 32 bit neon BUG=none TESTED=nacl neon build R=harryjin@google.com, tpsiaki@google.com
Fix for build on 32 bit neon
BUG=none
TESTED=nacl neon build
R=harryjin@google.com, tpsiaki@google.com

Review URL: https://webrtc-codereview.appspot.com/34659004
flykickbird/libyuv,flykickbird/libyuv,flykickbird/libyuv