drm/rockchip: remove of_match_ptr() from vop_driver_dt_match

kernel test robot throws warning when CONFIG_OF not set.

>> drivers/gpu/drm/rockchip/rockchip_vop_reg.c:1038:34:
warning: unused variable 'vop_driver_dt_match' [-Wunused-const-variable]
   static const struct of_device_id vop_driver_dt_match[] = {

Fixed it by removing of_match_ptr().

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210607190800.3992-1-jrdr.linux@gmail.com

drivers/gpu/drm/rockchip/rockchip_vop_reg.c

@@ -1124,6 +1124,6 @@ struct platform_driver vop_platform_driver = {
 	.remove = vop_remove,
 	.driver = {
 		.name = "rockchip-vop",
-		.of_match_table = of_match_ptr(vop_driver_dt_match),
+		.of_match_table = vop_driver_dt_match,
 	},
 };