igc: block setting preemptible traffic class in taprio

Since preemptible tc implementation is not ready yet, block it from being
set in taprio. The existing code already blocks it in mqprio.

Reviewed-by: Vladimir Oltean <[email protected]>
Signed-off-by: Faizal Rahim <[email protected]>
Tested-by: Mor Bar-Gabay <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: Faizal Rahim

drivers/net/ethernet/intel/igc/igc_main.c

@@ -6486,6 +6486,10 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter,
 	if (!validate_schedule(adapter, qopt))
 		return -EINVAL;
 
+	/* preemptible isn't supported yet */
+	if (qopt->mqprio.preemptible_tcs)
+		return -EOPNOTSUPP;
+
 	igc_ptp_read(adapter, &now);
 
 	if (igc_tsn_is_taprio_activated_by_user(adapter) &&