RDMA/i40iw: Associate ibdev to netdev before IB device registration

i40iw IB device registration fails with ENODEV.

ib_register_device
 setup_device/setup_port_data
  i40iw_port_immutable
   ib_query_port
     iw_query_port
      ib_device_get_netdev(ENODEV)

ib_device_get_netdev() does not have a netdev associated
with the ibdev and thus fails.
Use ib_device_set_netdev() to associate netdev to ibdev
in i40iw before IB device registration.

Fixes: 4929116 ("RDMA/core: Add common iWARP query port")
Link: https://lore.kernel.org/r/20190925164524.856-1-shiraz.saleem@intel.com
Signed-off-by: Shiraz, Saleem <shiraz.saleem@intel.com>
Reviewed-by: Kamal Heib <kamalheib1@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/i40iw/i40iw_verbs.c

@@ -2773,6 +2773,10 @@ int i40iw_register_rdma_device(struct i40iw_device *iwdev)
 		return -ENOMEM;
 	iwibdev = iwdev->iwibdev;
 	rdma_set_device_sysfs_group(&iwibdev->ibdev, &i40iw_attr_group);
+	ret = ib_device_set_netdev(&iwibdev->ibdev, iwdev->netdev, 1);
+	if (ret)
+		goto error;
+
 	ret = ib_register_device(&iwibdev->ibdev, "i40iw%d");
 	if (ret)
 		goto error;