igbvf: Enable TSO for stacked VLAN

Setting ndo_features_check to passthru_features_check allows the driver
to skip the check for multiple tagged TSO packets and enables stacked
VLAN TSO.
Tested with I350.

Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igbvf/netdev.c

@@ -2615,6 +2615,7 @@ static const struct net_device_ops igbvf_netdev_ops = {
 	.ndo_poll_controller	= igbvf_netpoll,
 #endif
 	.ndo_set_features	= igbvf_set_features,
+	.ndo_features_check	= passthru_features_check,
 };
 
 /**