net/smc: Replace ib_query_gid with rdma_get_gid_attr

Push the copy of the gid_attr into the SMC code. This probably doesn't
push it far enough, as it looks like the conn->lgr should potentially hold
the reference for its lifetime.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>