phy: phy-mtk-dp: change mtk_dp_phy_driver to static

mtk_dp_phy_driver is only used in phy-mtk-dp.c now, change it to static.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220707135309.801181-1-yangyingliang@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/mediatek/phy-mtk-dp.c

@@ -189,7 +189,7 @@ static int mtk_dp_phy_probe(struct platform_device *pdev)
 	return 0;
 }
 
-struct platform_driver mtk_dp_phy_driver = {
+static struct platform_driver mtk_dp_phy_driver = {
 	.probe = mtk_dp_phy_probe,
 	.driver = {
 		.name = "mediatek-dp-phy",