ixgbe: Not allow 8259x unsupported wol options change from ethtool

Wake-on-lan is currently only supported by 82599 KX4 devices, in all
other cases return a proper value from ixgbe_wol_exclusion function call.
Otherwise from ethtool we will be able to change wol options of
unsupported 8259x devices.

Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ixgbe/ixgbe_ethtool.c b/drivers/net/ixgbe/ixgbe_ethtool.c
index 0f7b6a3..2a97800 100644
--- a/drivers/net/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ixgbe/ixgbe_ethtool.c
@@ -1830,7 +1830,6 @@
 		break;
 	default:
 		wol->supported = 0;
-		retval = 0;
 	}
 
 	return retval;