Improve accuracy of J422 color space using higher precission fixed point and bias. BUG=414 TESTED=TestFullYUVJ R=tpsiaki@google.com
Improve accuracy of J422 color space using higher precission fixed point and bias.
BUG=414
TESTED=TestFullYUVJ
R=tpsiaki@google.com

Review URL: https://webrtc-codereview.appspot.com/44679004

git-svn-id: a51711482b6ba0e1d1ab095578a045eeae45ac9a@1327 16f28f9a-4ce2-e073-06de-1de4eb20be90

rig-project/libyuv,rig-project/libyuv,rig-project/libyuv