nfp: ethtool: expose transmit SO_TIMESTAMPING capability

NFP always supports software time stamping of tx, now expose
the capability through ethtool ops.

Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Link: https://lore.kernel.org/r/20231129080413.83789-1-louis.peens@corigine.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c

@@ -2502,6 +2502,7 @@ static const struct ethtool_ops nfp_net_ethtool_ops = {
 	.set_pauseparam		= nfp_port_set_pauseparam,
 	.get_pauseparam		= nfp_port_get_pauseparam,
 	.set_phys_id		= nfp_net_set_phys_id,
+	.get_ts_info		= ethtool_op_get_ts_info,
 };
 
 const struct ethtool_ops nfp_port_ethtool_ops = {