IB/mlx5: Report mlx5 multi packet WQE caps during query

The capabilities whether hardware support multi packet WQE or not is
exposed to user space through query_device by uhw.

Signed-off-by: Bodong Wang <bodong@mellanox.com>
Reviewed-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>