drm/rockchip: Fix module autoload for OF platform driver

This platform driver has a OF device ID table but the OF module
alias information is not created so module autoloading won't work.
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>

drivers/gpu/drm/rockchip/rockchip_drm_vop.c

@@ -374,6 +374,7 @@ static const struct of_device_id vop_driver_dt_match[] = {
 	  .data = &rk3288_vop },
 	{},
 };
+MODULE_DEVICE_TABLE(of, vop_driver_dt_match);
 
 static inline void vop_writel(struct vop *vop, uint32_t offset, uint32_t v)
 {