USB: rtl8150_disconnect() needs tasklet_kill()

We need to wait until any currently-running handler has completed.  Fixes an
unplug-time oops reported by "Miles Lane" <miles.lane@gmail.com>.

Cc: "Petko Manolov" <petkan@users.sourceforge.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/net/rtl8150.c

@@ -972,6 +972,7 @@ static void rtl8150_disconnect(struct usb_interface *intf)
 	if (dev) {
 		set_bit(RTL8150_UNPLUG, &dev->flags);
 		tasklet_disable(&dev->tl);
+		tasklet_kill(&dev->tl);
 		unregister_netdev(dev->netdev);
 		unlink_all_urbs(dev);
 		free_all_urbs(dev);