IB/mlx5: Fix returned values of query QP

Some variables were not initialized properly: max_recv_wr,
max_recv_sge, max_send_wr, qp_context and max_inline_data.

Fixes: e126ba97

 ('mlx5: Add driver for Mellanox Connect-IB...')
Signed-off-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>