[PATCH] isdn/gigaset: fix possible missing wakeup

Eliminate some possibilities for user processes writing to the Gigaset
character device to be left sleeping indefinitely, by adding wakeup calls
to error paths and properly disposing of pending write requests when the
device is disconnected.

It also removes unnecessary NULL checks before usb_free_urb() and
usb_kill_urb() calls.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Acked-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>