net: use SPEED_UNKNOWN and DUPLEX_UNKNOWN when appropriate

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/igbvf/ethtool.c

@@ -101,8 +101,8 @@ static int igbvf_get_settings(struct net_device *netdev,
 		else
 			ecmd->duplex = DUPLEX_HALF;
 	} else {
-		ethtool_cmd_speed_set(ecmd, -1);
-		ecmd->duplex = -1;
+		ethtool_cmd_speed_set(ecmd, SPEED_UNKNOWN);
+		ecmd->duplex = DUPLEX_UNKNOWN;
 	}
 
 	ecmd->autoneg = AUTONEG_DISABLE;