Improve the accuracy YUV to RGB for ARM64 NEON

ARM64 NEON version of YUV422TORGB is updated based on C algorithm.
Except TestJ420 and TestYUV, all the other tests are passed.

BUG=324
TESTED=libyuvTest on ARM64 with Android
R=fbarchard@google.com

Change-Id: Ia2663cfdeccc4c8c1d46262c9c0cc67b71d45e70

Review URL: https://webrtc-codereview.appspot.com/35329004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1304 16f28f9a-4ce2-e073-06de-1de4eb20be90