ifconfig: T2158: xen_netfront does not support setting pause/speed
ifconfig: T2158: xen_netfront does not support setting pause/speed

* Add xen_netfront to the list of interface types that will error reading pause via ethtool
* Also disable for speed, as it doesn't make sense (although the driver doesn't error.)
vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x