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>
diff --git a/drivers/net/ethernet/intel/e1000e/ethtool.c b/drivers/net/ethernet/intel/e1000e/ethtool.c
index e9a48bb..815e26c 100644
--- a/drivers/net/ethernet/intel/e1000e/ethtool.c
+++ b/drivers/net/ethernet/intel/e1000e/ethtool.c
@@ -159,8 +159,8 @@
 		ecmd->transceiver = XCVR_EXTERNAL;
 	}
 
-	speed = -1;
-	ecmd->duplex = -1;
+	speed = SPEED_UNKNOWN;
+	ecmd->duplex = DUPLEX_UNKNOWN;
 
 	if (netif_running(netdev)) {
 		if (netif_carrier_ok(netdev)) {