Now that urb->status isn't used, urb->lock doesn't protect anything.
This patch (as980) removes it and replaces it with a private mutex in
the one remaining place it was still used: usb_kill_urb.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>