ARGBUnattenuateRow_C use same table as ARGBUnattenuateRow_SSE2.  omit-frame-pointer for ScaleRowDown38_3_Int_NEON
BUG=35
TESTED=disable asm and run unittest on x86
Review URL: https://webrtc-codereview.appspot.com/585004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@268 16f28f9a-4ce2-e073-06de-1de4eb20be90