gianfar: Check if phydev present on ethtool -A

commit 98a46d46 upstream.

This fixes a seg fault on 'ethtool -A' entry if the
interface is down.  Obviously we need to have the
phy device initialized / "connected" (see of_phy_connect())
to be able to advertise pause frame capabilities.

Fixes: 23402bddSigned-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/net/ethernet/freescale/gianfar_ethtool.c

@@ -553,6 +553,9 @@ static int gfar_spauseparam(struct net_device *dev,
 	struct gfar __iomem *regs = priv->gfargrp[0].regs;
 	u32 oldadv, newadv;
 
+	if (!phydev)
+		return -ENODEV;
+
 	if (!(phydev->supported & SUPPORTED_Pause) ||
 	    (!(phydev->supported & SUPPORTED_Asym_Pause) &&
 	     (epause->rx_pause != epause->tx_pause)))