Hold reference to the the sgid_attr which is used in a cm_id until the
cm_id is destroyed.
Signed-off-by: NParav Pandit <parav@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>