usb: xhci: Free the right ring in xhci_add_endpoint()

In the xhci_add_endpoint(), a new ring was allocated and saved at
xhci_virt_ep->new_ring. Hence, when error happens, we need to free
the allocated ring before returning error.

Current code frees xhci_virt_ep->ring instead of the new_ring. This
patch fixes this.

Cc: <stable@vger.kernel.org>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci.c

@@ -1703,7 +1703,8 @@ static int xhci_add_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
 	if (xhci->quirks & XHCI_MTK_HOST) {
 		ret = xhci_mtk_add_ep_quirk(hcd, udev, ep);
 		if (ret < 0) {
-			xhci_free_endpoint_ring(xhci, virt_dev, ep_index);
+			xhci_ring_free(xhci, virt_dev->eps[ep_index].new_ring);
+			virt_dev->eps[ep_index].new_ring = NULL;
 			return ret;
 		}
 	}