net: enetc: simplify enetc_num_stack_tx_queues()

We keep a pointer to the xdp_prog in the private netdev structure as
well; what's replicated per RX ring is done so just for more convenient
access from the NAPI poll procedure.

Simplify enetc_num_stack_tx_queues() by looking at priv->xdp_prog rather
than iterating through the information replicated per RX ring.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/enetc/enetc.c

@@ -28,11 +28,9 @@ EXPORT_SYMBOL_GPL(enetc_port_mac_wr);
 static int enetc_num_stack_tx_queues(struct enetc_ndev_priv *priv)
 {
 	int num_tx_rings = priv->num_tx_rings;
-	int i;
 
-	for (i = 0; i < priv->num_rx_rings; i++)
-		if (priv->rx_ring[i]->xdp.prog)
-			return num_tx_rings - num_possible_cpus();
+	if (priv->xdp_prog)
+		return num_tx_rings - num_possible_cpus();
 
 	return num_tx_rings;
 }