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/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
index 23e4e6a..a452730 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
@@ -296,8 +296,8 @@
 		}
 		ecmd->duplex = DUPLEX_FULL;
 	} else {
-		ethtool_cmd_speed_set(ecmd, -1);
-		ecmd->duplex = -1;
+		ethtool_cmd_speed_set(ecmd, SPEED_UNKNOWN);
+		ecmd->duplex = DUPLEX_UNKNOWN;
 	}
 
 	return 0;