[CFL] Add 4:2:2 Support
[CFL] Add 4:2:2 Support

When 4:2:2 subsampling is used, both horizontal pixels are added and
shifted left by 1 (instead of a right shift of 2 followed by a left
shift of 3).

Change-Id: Ib84c51cafabe0bd0de02dfe7868278e44d76f6db

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom