usb: dwc3: pci: fix another failure path in dwc3_pci_probe()

When applying commit 7d26b587 (fix failure path in
dwc3_pci_probe()), I mistakenly left out one of the
possible failures where we would return success even
on the error case.

This patch fixes that mistake.
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/dwc3-pci.c

@@ -89,6 +89,7 @@ static int __devinit dwc3_pci_probe(struct pci_dev *pci,
 	dwc3 = platform_device_alloc("dwc3", devid);
 	if (!dwc3) {
 		dev_err(dev, "couldn't allocate dwc3 device\n");
+		ret = -ENOMEM;
 		goto err1;
 	}