Not all drivers will need take all the modeset locks for dirtyfb, so
push the locking down to the drivers.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NJakob Bornecrantz <jakob@vmware.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>