USB: BKL removal from ioctl path of usbfs

Total removal from the ioctl code path except for the outcall
to external modules. Locking is ensured by the normal locks
of usbfs.

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>