We still had one lingering RMW in ivb_sprite_disable(), all the other
RMWs were killed off from the sprite code some time ago. Kill the
straggler too.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>