net: fec: ensure that a disconnected phy isn't configured

When we disconnect from a phy, we should forget our pointer to it so we
don't accidentally try to configure it.  We handle a NULL phy pointer
correctly in most places, except fec_enet_set_pauseparam().  Fix this
too.

Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec_main.c

@@ -1875,6 +1875,9 @@ static int fec_enet_set_pauseparam(struct net_device *ndev,
 {
 	struct fec_enet_private *fep = netdev_priv(ndev);
 
+	if (!fep->phy_dev)
+		return -ENODEV;
+
 	if (pause->tx_pause != pause->rx_pause) {
 		netdev_info(ndev,
 			"hardware only support enable/disable both tx and rx");
@@ -2186,6 +2189,7 @@ fec_enet_close(struct net_device *ndev)
 
 	phy_stop(fep->phy_dev);
 	phy_disconnect(fep->phy_dev);
+	fep->phy_dev = NULL;
 
 	fec_enet_clk_enable(ndev, false);
 	pinctrl_pm_select_sleep_state(&fep->pdev->dev);