net/core: tidy up an error message

netif_napi_add() could report an error like this below due to it allows
to pass a format string for wildcarding before calling
dev_get_valid_name(),

"netif_napi_add() called with weight 256 on device eth%d"

For example, hns_enet_drv module does this.

hns_nic_try_get_ae
  hns_nic_init_ring_data
    netif_napi_add
  register_netdev
    dev_get_valid_name

Hence, make it a bit more human-readable by using netdev_err_once()
instead.
Signed-off-by: Qian Cai <cai@gmx.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -6209,8 +6209,8 @@ void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
 	napi->skb = NULL;
 	napi->poll = poll;
 	if (weight > NAPI_POLL_WEIGHT)
-		pr_err_once("netif_napi_add() called with weight %d on device %s\n",
-			    weight, dev->name);
+		netdev_err_once(dev, "%s() called with weight %d\n", __func__,
+				weight);
 	napi->weight = weight;
 	list_add(&napi->dev_list, &dev->napi_list);
 	napi->dev = dev;