Accelerated raster ops doesn't work on WM8750/WM8850

[tonyprisk]

When enabling accelerated raster operations on the new SoC's, the fill function does not work correctly.

If the console, this is evident by the end of lines continuing to scroll up the screen without being cleared properly.

[tonyprisk]

Tested WM8750 with VGA output - no problems with or without accelerated raster ops.
Looks like this problem only occurs on the WM8850.

Wondermedia vendor kernel uses the CFB versions of fill_rect and copy_area so it's possible they know there is a problem, but didn't bother to fix it :/