net/mlx5: Add support in forward to namespace

Currently, fs_core supports rule of forward the traffic
to continue matching in the next priority, now we add support
to forward the traffic matching in the next namespace.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Mark Zhang <markz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>