net: add netif_tx_napi_add()

netif_tx_napi_add() is a variant of netif_napi_add()

It should be used by drivers that use a napi structure
to exclusively poll TX.

We do not want to add this kind of napi in napi_hash[] in following
patches, adding generic busy polling to all NAPI drivers.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index 17f017a..b15a60d 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -2041,11 +2041,11 @@
 
 	for (i = 0; i < priv->hw_params->tx_queues; ++i) {
 		ring = &priv->tx_rings[i];
-		netif_napi_add(priv->dev, &ring->napi, bcmgenet_tx_poll, 64);
+		netif_tx_napi_add(priv->dev, &ring->napi, bcmgenet_tx_poll, 64);
 	}
 
 	ring = &priv->tx_rings[DESC_INDEX];
-	netif_napi_add(priv->dev, &ring->napi, bcmgenet_tx_poll, 64);
+	netif_tx_napi_add(priv->dev, &ring->napi, bcmgenet_tx_poll, 64);
 }
 
 static void bcmgenet_enable_tx_napi(struct bcmgenet_priv *priv)