e1000e: return appropriate errors for 'ethtool -r'

...when invoked while interface is not up or when auto-negotiation is
disabled as done by other drivers.
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/e1000e/ethtool.c

@@ -1963,8 +1963,15 @@ static int e1000_set_coalesce(struct net_device *netdev,
 static int e1000_nway_reset(struct net_device *netdev)
 {
 	struct e1000_adapter *adapter = netdev_priv(netdev);
-	if (netif_running(netdev))
-		e1000e_reinit_locked(adapter);
+
+	if (!netif_running(netdev))
+		return -EAGAIN;
+
+	if (!adapter->hw.mac.autoneg)
+		return -EINVAL;
+
+	e1000e_reinit_locked(adapter);
+
 	return 0;
 }