ixgbe: fix ethtool disable csum for ipv6

ethtool was not disabling the correct netif flags when setting
checksum disable.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/ixgbe/ixgbe_ethtool.c b/drivers/net/ixgbe/ixgbe_ethtool.c
index 64460b4..2506f9e 100644
--- a/drivers/net/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ixgbe/ixgbe_ethtool.c
@@ -241,7 +241,7 @@
 	if (data)
 		netdev->features |= (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM);
 	else
-		netdev->features &= ~NETIF_F_IP_CSUM;
+		netdev->features &= ~(NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM);
 
 	return 0;
 }