IB/mlx5: Advertise atomic capabilities in query device

In order to ensure IB spec atomic correctness in atomic operations, if
HW is configured to host endianness, advertise IB_ATOMIC_HCA.  if not,
advertise IB_ATOMIC_NONE.

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>