usbip: fix NULL pointer dereference on errors

Fix NULL pointer dereference and obsolete comments forgotten when
usbip server was converted from an interface driver to a device driver.

Signed-off-by: Alexander Popov <alpopov@ptsecurity.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/usbip/stub_dev.c b/drivers/usb/usbip/stub_dev.c
index e286346..c653ce5 100644
--- a/drivers/usb/usbip/stub_dev.c
+++ b/drivers/usb/usbip/stub_dev.c
@@ -219,7 +219,7 @@
 
 	dev_dbg(&udev->dev, "device reset");
 
-	ret = usb_lock_device_for_reset(udev, sdev->interface);
+	ret = usb_lock_device_for_reset(udev, NULL);
 	if (ret < 0) {
 		dev_err(&udev->dev, "lock for reset\n");
 		spin_lock_irq(&ud->lock);
@@ -252,7 +252,7 @@
 
 /**
  * stub_device_alloc - allocate a new stub_device struct
- * @interface: usb_interface of a new device
+ * @udev: usb_device of a new device
  *
  * Allocates and initializes a new stub_device struct.
  */