drivers: net: Remove device_node checks with of_mdiobus_register()

A number of drivers have the following pattern:

if (np)
	of_mdiobus_register()
else
	mdiobus_register()

which the implementation of of_mdiobus_register() now takes care of.
Remove that pattern in drivers that strictly adhere to it.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
Reviewed-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 9176143..8dff87e 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -1843,12 +1843,9 @@ static int lan78xx_mdio_init(struct lan78xx_net *dev)
 	}
 
 	node = of_get_child_by_name(dev->udev->dev.of_node, "mdio");
-	if (node) {
-		ret = of_mdiobus_register(dev->mdiobus, node);
+	ret = of_mdiobus_register(dev->mdiobus, node);
+	if (node)
 		of_node_put(node);
-	} else {
-		ret = mdiobus_register(dev->mdiobus);
-	}
 	if (ret) {
 		netdev_err(dev->net, "can't register MDIO bus\n");
 		goto exit1;