tg3: Use pci_dev_id() to simplify the code

PCI core API pci_dev_id() can be used to get the BDF number for a pci
device. We don't need to compose it manually. Use pci_dev_id() to
simplify the code a little bit.
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/tg3.c

@@ -1539,8 +1539,7 @@ static int tg3_mdio_init(struct tg3 *tp)
 		return -ENOMEM;
 
 	tp->mdio_bus->name     = "tg3 mdio bus";
-	snprintf(tp->mdio_bus->id, MII_BUS_ID_SIZE, "%x",
-		 (tp->pdev->bus->number << 8) | tp->pdev->devfn);
+	snprintf(tp->mdio_bus->id, MII_BUS_ID_SIZE, "%x", pci_dev_id(tp->pdev));
 	tp->mdio_bus->priv     = tp;
 	tp->mdio_bus->parent   = &tp->pdev->dev;
 	tp->mdio_bus->read     = &tg3_mdio_read;