net: stmmac: use "mdio_bus_data" local variable

We have a local variable for priv->plat->mdio_bus_data, which we use
later in the conditional if() block, but we evaluate the above within
the conditional expression. Use mdio_bus_data instead. Since these
will be the only two users of this local variable, move its assignment
just before the if().
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/E1qZAXJ-005pU1-1z@rmk-PC.armlinux.org.ukSigned-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -1199,7 +1199,7 @@ static int stmmac_init_phy(struct net_device *dev)
 
 static int stmmac_phy_setup(struct stmmac_priv *priv)
 {
-	struct stmmac_mdio_bus_data *mdio_bus_data = priv->plat->mdio_bus_data;
+	struct stmmac_mdio_bus_data *mdio_bus_data;
 	int max_speed = priv->plat->max_speed;
 	int mode = priv->plat->phy_interface;
 	struct fwnode_handle *fwnode;
@@ -1207,7 +1207,9 @@ static int stmmac_phy_setup(struct stmmac_priv *priv)
 
 	priv->phylink_config.dev = &priv->dev->dev;
 	priv->phylink_config.type = PHYLINK_NETDEV;
-	if (priv->plat->mdio_bus_data)
+
+	mdio_bus_data = priv->plat->mdio_bus_data;
+	if (mdio_bus_data)
 		priv->phylink_config.ovr_an_inband =
 			mdio_bus_data->xpcs_an_inband;