usb: gadget: fix ptr_ret.cocci warnings

drivers/usb/gadget/udc/r8a66597-udc.c:1849:1-3: WARNING: PTR_ERR_OR_ZERO can be used

 Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR

Generated by: scripts/coccinelle/api/ptr_ret.cocci
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

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

@@ -1845,10 +1845,7 @@ static int r8a66597_sudmac_ioremap(struct r8a66597 *r8a66597,
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "sudmac");
 	r8a66597->sudmac_reg = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(r8a66597->sudmac_reg))
-		return PTR_ERR(r8a66597->sudmac_reg);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(r8a66597->sudmac_reg);
 }
 
 static int r8a66597_probe(struct platform_device *pdev)