Make sure that dequeued urbs get handled first
by collect_qtds. To achieve that we better move them
up to the head in the qh list.

This for instance fixes hanging serial devices, which wait
for dequeued urbs to properly close their device node.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>