net/mlx4_core: Remove port type restrictions

Port1=Eth, Port2=IB restriction is no longer required.
Having RoCE, there will always rdma port initialized over ConnectX
physical port, no matter whether the link layer is IB or Ethernet.
So we always have dual port IB device.

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>