igc: Use num_tx_queues when iterating over tx_ring queue

Use num_tx_queues rather than the IGC_MAX_TX_QUEUES fixed number 4 when
iterating over tx_ring queue since instantiated queue count could be
less than 4 where on-line cpu count is less than 4.

Fixes: ec50a9d ("igc: Add support for taprio offloading")
Signed-off-by: Toshiki Nishioka <toshiki.nishioka@intel.com>
Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Tested-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Acked-by: Sasha Neftin <sasha.neftin@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

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

@@ -5495,7 +5495,7 @@ static bool validate_schedule(struct igc_adapter *adapter,
 		if (e->command != TC_TAPRIO_CMD_SET_GATES)
 			return false;
 
-		for (i = 0; i < IGC_MAX_TX_QUEUES; i++) {
+		for (i = 0; i < adapter->num_tx_queues; i++) {
 			if (e->gate_mask & BIT(i))
 				queue_uses[i]++;
 
@@ -5552,7 +5552,7 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter,
 
 		end_time += e->interval;
 
-		for (i = 0; i < IGC_MAX_TX_QUEUES; i++) {
+		for (i = 0; i < adapter->num_tx_queues; i++) {
 			struct igc_ring *ring = adapter->tx_ring[i];
 
 			if (!(e->gate_mask & BIT(i)))