Require users to register with SA module, to prevent the sa_query
module text from going away while an SA query callback is still
running.  Update all in-tree users for the new interface.
Signed-off-by: NMichael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>