uxa: port over tiled fill code from EXA
uxa: port over tiled fill code from EXA

This makes X -retro actually render fast, as opposed to glacially slow.

Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

facboy/xserver-xorg-video-qxl,facboy/xserver-xorg-video-qxl,fgouget/xf86-video-qxl,facboy/xserver-xorg-video-qxl,facboy/xserver-xorg-video-qxl,fgouget/xf86-video-qxl,fgouget/xf86-video-qxl,fgouget/xf86-video-qxl