drm/omap: dss: Constify omap_dss_driver operations structure

The structure contains function pointers that don't need to be modified.
Make all its instances const to improve security.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/displays/panel-nec-nl8048hl11.c

@@ -222,7 +222,7 @@ static int nec_8048_check_timings(struct omap_dss_device *dssdev,
 	return in->ops.dpi->check_timings(in, vm);
 }
 
-static struct omap_dss_driver nec_8048_ops = {
+static const struct omap_dss_driver nec_8048_ops = {
 	.connect	= nec_8048_connect,
 	.disconnect	= nec_8048_disconnect,