net: dsa: mv88e6xxx: add ATU setup helper

Move the configuration of the default ageing time in a new
mv88e6xxx_atu_setup function.

That function will be extended later to contain all ATU related
configuration bits.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/chip.c

@@ -1306,6 +1306,11 @@ static void mv88e6xxx_port_stp_state_set(struct dsa_switch *ds, int port,
 		netdev_err(ds->ports[port].netdev, "failed to update state\n");
 }
 
+static int mv88e6xxx_atu_setup(struct mv88e6xxx_chip *chip)
+{
+	return mv88e6xxx_g1_atu_set_age_time(chip, 300000);
+}
+
 static void mv88e6xxx_port_fast_age(struct dsa_switch *ds, int port)
 {
 	struct mv88e6xxx_chip *chip = ds->priv;
@@ -2756,10 +2761,6 @@ static int mv88e6xxx_g1_setup(struct mv88e6xxx_chip *chip)
 	if (err)
 		return err;
 
-	err = mv88e6xxx_g1_atu_set_age_time(chip, 300000);
-	if (err)
-		return err;
-
 	/* Clear all ATU entries */
 	err = _mv88e6xxx_atu_flush(chip, 0, true);
 	if (err)
@@ -2845,6 +2846,10 @@ static int mv88e6xxx_setup(struct dsa_switch *ds)
 			goto unlock;
 	}
 
+	err = mv88e6xxx_atu_setup(chip);
+	if (err)
+		goto unlock;
+
 	/* Some generations have the configuration of sending reserved
 	 * management frames to the CPU in global2, others in
 	 * global1. Hence it does not fit the two setup functions