net: dpaa2-switch replace direct MAC access with dpaa2_switch_port_has_mac()

The helper function will gain a lockdep annotation in a future patch.
Make sure to benefit from it.
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Tested-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/freescale/dpaa2/dpaa2-switch-ethtool.c

@@ -189,7 +189,7 @@ static void dpaa2_switch_ethtool_get_stats(struct net_device *netdev,
 				   dpaa2_switch_ethtool_counters[i].name, err);
 	}
 
-	if (port_priv->mac)
+	if (dpaa2_switch_port_has_mac(port_priv))
 		dpaa2_mac_get_ethtool_stats(port_priv->mac, data + i);
 }