drm_atomic_get_plane_state() may return ERR_PTR. Handle
drm_atomic_get_plane_state() return values right in
omap_crtc_atomic_set_property().
Signed-off-by: NJyri Sarha <jsarha@ti.com>
Acked-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>