uhci: fix uhci_async_cancel_all

It should also free all queues.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb/hcd-uhci.c

@@ -300,6 +300,7 @@ static void uhci_async_cancel_all(UHCIState *s)
             uhci_async_unlink(curr);
             uhci_async_cancel(curr);
         }
+        uhci_queue_free(queue);
     }
 }