usb: gadget: r8a66597-udc: 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 <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904094738.7860-1-yuehaibing@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/r8a66597-udc.c

@@ -1838,7 +1838,7 @@ static int r8a66597_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	char clk_name[8];
-	struct resource *res, *ires;
+	struct resource *ires;
 	int irq;
 	void __iomem *reg = NULL;
 	struct r8a66597 *r8a66597 = NULL;
@@ -1846,8 +1846,7 @@ static int r8a66597_probe(struct platform_device *pdev)
 	int i;
 	unsigned long irq_trigger;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	reg = devm_ioremap_resource(&pdev->dev, res);
+	reg = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(reg))
 		return PTR_ERR(reg);