stmmac: use netif_set_real_num_{rx,tx}_queues

A driver must not access the two fields directly but should instead use
the helper functions to set the values and keep a consistent internal
state:

ethernet/stmicro/stmmac/stmmac_main.c: In function 'stmmac_dvr_probe':
ethernet/stmicro/stmmac/stmmac_main.c:4083:8: error: 'struct net_device' has no member named 'real_num_rx_queues'; did you mean 'real_num_tx_queues'?

Fixes: a8f5102af2a7 ("net: stmmac: TX and RX queue priority configuration")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -4080,8 +4080,8 @@ int stmmac_dvr_probe(struct device *device,
 		goto error_hw_init;
 
 	/* Configure real RX and TX queues */
-	ndev->real_num_rx_queues = priv->plat->rx_queues_to_use;
-	ndev->real_num_tx_queues = priv->plat->tx_queues_to_use;
+	netif_set_real_num_rx_queues(ndev, priv->plat->rx_queues_to_use);
+	netif_set_real_num_tx_queues(ndev, priv->plat->tx_queues_to_use);
 
 	priv->dma_buf_sz = STMMAC_ALIGN(buf_sz);