Now that the integrity profile is statically allocated there is no work
to do when shutting down an integrity enabled block device.

Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: James Bottomley <JBottomley@Odin.com>
Acked-by: NNeilBrown <neilb@suse.com>
Acked-by: NKeith Busch <keith.busch@intel.com>
Acked-by: NVishal Verma <vishal.l.verma@intel.com>
Tested-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJens Axboe <axboe@fb.com>