Revert VP8 part of "image2yuvconfig() should calculate ..."

This partially reverts commit f662898c395f824058c997885c66c2c4c5e6e69c.

The VP8 part of the change causes use of uninitialized data in various
parts of the encoder due to y/uv_width/height including the border after
that commit and those values being used instead of
y/uv_crop_width/height.

Bug: 520751602, 517413744
Change-Id: I9b34fa78a453fb711f3b28bf058e755d1beac746