INSTPM is a masked register so use the _MASKED_BIT_{ENABLE,DISABLE}
macros when enabling/disabling self-refresh on 915GM.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>