hwc: Split display: Correct source crops split, enable overfetch

For split source crop of YUV ensure that Left and Width
(thus Right) of each crop is even.

For split source crop of RGB and YUV ensure that Crops have
no gaps (i.e right of left-crop = left of right-crop)

Enable overfetch of pixels in the center, for split layers,
to get a smooth upscale

Change-Id: I8e4a91b637c840f75742580645c6468b5769432d
2 files changed