Half of the functionality was duplicated.
The rest is about the alpha channel handling so we
might as well put it in the appropriate file.
Change-Id: I8d5ef0afce82cc4842ab7132fd97995c42e6140a
generates a stub function when the specific architecture is not enabled,
exposing a symbol in the module, avoiding a compiler warning
Change-Id: Ia9336e57466a9b5241b85c1c95838e91c9283147