Up until now, flow steering wasn't supported when using IB ports.

This patch enables support for flow steering if all hardware ports
support that, for example the new MLX4_DEV_CAP_FLAG2_DMFS_IPOIB mlx4
device capability.
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>