usb: gadget: r8a66597-udc: fix error return code in r8a66597_probe()

Fix to return -ENOMEM in the request alloc error handling
case instead of 0, as done elsewhere in this function.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/gadget/r8a66597-udc.c b/drivers/usb/gadget/r8a66597-udc.c
index 0b742d1..7ff7d9c 100644
--- a/drivers/usb/gadget/r8a66597-udc.c
+++ b/drivers/usb/gadget/r8a66597-udc.c
@@ -1977,8 +1977,10 @@
 
 	r8a66597->ep0_req = r8a66597_alloc_request(&r8a66597->ep[0].ep,
 							GFP_KERNEL);
-	if (r8a66597->ep0_req == NULL)
+	if (r8a66597->ep0_req == NULL) {
+		ret = -ENOMEM;
 		goto clean_up3;
+	}
 	r8a66597->ep0_req->complete = nop_completion;
 
 	ret = usb_add_gadget_udc(&pdev->dev, &r8a66597->gadget);