soc: mediatek: mmsys: Use devm_platform_ioremap_resource()

For the common platform_get_resource()+devm_platform_ioremap() combination,
there is a helper, so use it and make the code a bit more compact.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Link: https://lore.kernel.org/r/20201006193320.405529-3-enric.balletbo@collabora.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

drivers/soc/mediatek/mtk-mmsys.c

@@ -306,15 +306,12 @@ static int mtk_mmsys_probe(struct platform_device *pdev)
 	struct platform_device *clks;
 	struct platform_device *drm;
 	void __iomem *config_regs;
-	struct resource *mem;
 	int ret;
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	config_regs = devm_ioremap_resource(dev, mem);
+	config_regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(config_regs)) {
 		ret = PTR_ERR(config_regs);
-		dev_err(dev, "Failed to ioremap mmsys-config resource: %d\n",
-			ret);
+		dev_err(dev, "Failed to ioremap mmsys registers: %d\n", ret);
 		return ret;
 	}