phy: mdio-mux-meson-g12a: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: YueHaibing <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/phy/mdio-mux-meson-g12a.c

···
 {
 	struct device *dev = &pdev->dev;
 	struct g12a_mdio_mux *priv;
-	struct resource *res;
 	int ret;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
···
 
 	platform_set_drvdata(pdev, priv);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	priv->regs = devm_ioremap_resource(dev, res);
+	priv->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->regs))
 		return PTR_ERR(priv->regs);