net/mlx5: Refactor create flow table method to accept underlay QP

IB flow tables need the underlay qp to perform flow steering.
Here we change the API of the flow tables creation to accept the
underlay QP number as a parameter in order to support IB (IPoIB) flow
steering.

Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>