net: stmmac: reduce indentation when calling stmmac_xpcs_setup

There is no reason to embed an if within an if, we can just logically
AND the two conditions.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -7003,13 +7003,11 @@ int stmmac_dvr_probe(struct device *device,
 	if (priv->plat->speed_mode_2500)
 		priv->plat->speed_mode_2500(ndev, priv->plat->bsp_priv);
 
-	if (priv->plat->mdio_bus_data) {
-		if (priv->plat->mdio_bus_data->has_xpcs) {
+	if (priv->plat->mdio_bus_data && priv->plat->mdio_bus_data->has_xpcs) {
 		ret = stmmac_xpcs_setup(priv->mii);
 		if (ret)
 			goto error_xpcs_setup;
 	}
-	}
 
 	ret = stmmac_phy_setup(priv);
 	if (ret) {