forcedeth: advertise transmit time stamping

This driver now offers software transmit time stamping, so it should
advertise that fact via ethtool. Compile tested only.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>

Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/nvidia/forcedeth.c

@@ -5182,6 +5182,7 @@ static const struct ethtool_ops ops = {
 	.get_ethtool_stats = nv_get_ethtool_stats,
 	.get_sset_count = nv_get_sset_count,
 	.self_test = nv_self_test,
+	.get_ts_info = ethtool_op_get_ts_info,
 };
 
 /* The mgmt unit and driver use a semaphore to access the phy during init */