cxgb4/cxgb4vf: Assign netdev->dev_port with port ID

Added missing dev_port assignment in cxgb4vf driver.
Also made dev_port assignment of cxgb4 in sync with cxgb4vf driver.

Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Arjun V <arjun@chelsio.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>