net/mlx5: Add proper NIC TX steering flow tables support

Extend the ability to add steering rules to NIC TX flow tables.
For now, we are only adding TX bypass (egress) which is used by the RDMA
side. This will allow to shape outgoing traffic and tweak it if needed, for
example performing encapsulation or rewriting headers.

Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>