The only usage of dm_ksm_ll_ops is to make a copy of it to the ksm_ll_ops
field in the blk_keyslot_manager struct. Make it const to allow the
compiler to put it in read-only memory.
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>