If the waker is killed before it can replay outstanding URBs, these URBs
won't be freed or will be replayed at the next open.  This patch closes
the window by explicitely discarding outstanding URBs.
Signed-off-by: NOliver Neukum <oliver@neukum.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>