net/mlx4: change device reference for secondary process

net/mlx4: change device reference for secondary process

rte_eth_devices[] is not shared between primary and secondary process,
but a static array to each process. The reverse pointer of device
(priv->dev) becomes invalid if mlx4 supports secondary process.
Instead, priv has the pointer to shared data of the device,
  struct rte_eth_dev_data *dev_data;

Two macros are added,
  #define PORT_ID(priv) ((priv)->dev_data->port_id)
  #define ETH_DEV(priv) (&rte_eth_devices[PORT_ID(priv)])

Cc: stable@dpdk.org
Suggested-by: Raslan Darawsheh <rasland@mellanox.com>
Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>