staging: octeon: Call SET_NETDEV_DEV()

The Octeon driver calls into PHYLIB which now checks for
net_device->dev.parent, so make sure we do set it before calling into
any MDIO/PHYLIB related function.

Fixes: ec988ad78ed6 ("phy: Don't increment MDIO bus refcount unless it's a different owner")
Reported-by: Aaro Koskinen <[e-mail]>
Cc: stable <[e-mail]> # 4.9+
Signed-off-by: Florian Fainelli <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/octeon/ethernet.c

···
 			/* Initialize the device private structure. */
 			struct octeon_ethernet *priv = netdev_priv(dev);
 
+			SET_NETDEV_DEV(dev, &pdev->dev);
 			dev->netdev_ops = &cvm_oct_pow_netdev_ops;
 			priv->imode = CVMX_HELPER_INTERFACE_MODE_DISABLED;
 			priv->port = CVMX_PIP_NUM_INPUT_PORTS;
···
 			}
 
 			/* Initialize the device private structure. */
+			SET_NETDEV_DEV(dev, &pdev->dev);
 			priv = netdev_priv(dev);
 			priv->netdev = dev;
 			priv->of_node = cvm_oct_node_for_port(pip, interface,