USB: misc/adutux, fix lock imbalance

Don't unlock adutux_mutex when not held.

Signed-off-by: Jiri Slaby <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/misc/adutux.c

···
 	if (dev->open_count <= 0) {
 		dbg(1," %s : device not opened", __func__);
 		retval = -ENODEV;
-		goto exit;
+		goto unlock;
 	}
 
 	adu_release_internal(dev);
···
 		if (!dev->open_count)	/* ... and we're the last user */
 			adu_delete(dev);
 	}
-
-exit:
+unlock:
 	mutex_unlock(&adutux_mutex);
+exit:
 	dbg(2," %s : leave, return value %d", __func__, retval);
 	return retval;
 }