drm/xen: Don't set the dpms hook

Doesn't do anything for atomic.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Cc: xen-devel@lists.xen.org
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181210100359.22507-7-daniel.vetter@ffwll.ch

drivers/gpu/drm/xen/xen_drm_front_conn.c

@@ -89,7 +89,6 @@ static const struct drm_connector_helper_funcs connector_helper_funcs = {
 };
 
 static const struct drm_connector_funcs connector_funcs = {
-	.dpms = drm_helper_connector_dpms,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.destroy = drm_connector_cleanup,
 	.reset = drm_atomic_helper_connector_reset,