mlx4: trigger IB events needed by SMC

The mlx4 driver does not trigger an IB_EVENT_PORT_ACTIVE when the RoCE
network interface is activated. When SMC determines the RoCE device port
to be used, it checks the port states. This patch triggers IB events for
NETDEV_UP and NETDEV_DOWN.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Acked-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>