Avoid unnecessary copying of predicted pixels when there are no coeffs.
Avoid unnecessary copying of predicted pixels when there are no coeffs.

- These are probably from a time when reconstruction happened in this
  function.

lu-zero/kvazaar,ultravideo/kvazaar,ultravideo/kvazaar,lu-zero/kvazaar,lu-zero/kvazaar,ultravideo/kvazaar,ultravideo/kvazaar,lu-zero/kvazaar,ultravideo/kvazaar