phy: phy-mtk-tphy: get optional clock by devm_clk_get_optional()

Use devm_clk_get_optional() to get optional clock
Signed-off-by: NChunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>

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

@@ -1103,13 +1103,9 @@ static int mtk_tphy_probe(struct platform_device *pdev)
 	}
 
 	/* it's deprecated, make it optional for backward compatibility */
-	tphy->u3phya_ref = devm_clk_get(dev, "u3phya_ref");
-	if (IS_ERR(tphy->u3phya_ref)) {
-		if (PTR_ERR(tphy->u3phya_ref) == -EPROBE_DEFER)
-			return -EPROBE_DEFER;
-
-		tphy->u3phya_ref = NULL;
-	}
+	tphy->u3phya_ref = devm_clk_get_optional(dev, "u3phya_ref");
+	if (IS_ERR(tphy->u3phya_ref))
+		return PTR_ERR(tphy->u3phya_ref);
 
 	tphy->src_ref_clk = U3P_REF_CLK;
 	tphy->src_coef = U3P_SLEW_RATE_COEF;