usb: gadget: gr_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>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/udc/gr_udc.c

@@ -2118,7 +2118,6 @@ static int gr_request_irq(struct gr_udc *dev, int irq)
 static int gr_probe(struct platform_device *pdev)
 {
 	struct gr_udc *dev;
-	struct resource *res;
 	struct gr_regs __iomem *regs;
 	int retval;
 	u32 status;
@@ -2128,8 +2127,7 @@ static int gr_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	dev->dev = &pdev->dev;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	regs = devm_ioremap_resource(dev->dev, res);
+	regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(regs))
 		return PTR_ERR(regs);