mlx4: Set user-space raw Ethernet QPs to properly handle VXLAN traffic

Raw Ethernet QPs opened from user-space lack the proper setup to
recieve/handle VXLAN traffic when VXLAN offloads are enabled.

Fix that by adding a tunnel steering rule on top of the normal unicast
steering rule and set the tunnel_type field in the QP context.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>