net: dsa: b53: fix bcm63xx RGMII port link adjustment

BCM63XX's switch does not support MDIO scanning of external phys, so its
MACs needs to be manually configured for autonegotiated link speeds.

So b53_force_port_config() and b53_force_link() accordingly also when
mode is MLO_AN_PHY for those ports.

Fixes lower speeds than 1000/full on rgmii ports 4 - 7.

This aligns the behaviour with the old bcm63xx_enetsw driver for those
ports.

Fixes: 967dd82 ("net: dsa: b53: Add support for Broadcom RoboSwitch")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20251101132807.50419-3-jonas.gorski@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: KanjiMonster

drivers/net/dsa/b53/b53_common.c

@@ -1602,8 +1602,11 @@ static void b53_phylink_mac_link_down(struct phylink_config *config,
 	struct b53_device *dev = dp->ds->priv;
 	int port = dp->index;
 
-	if (mode == MLO_AN_PHY)
+	if (mode == MLO_AN_PHY) {
+		if (is63xx(dev) && in_range(port, B53_63XX_RGMII0, 4))
+			b53_force_link(dev, port, false);
 		return;
+	}
 
 	if (mode == MLO_AN_FIXED) {
 		b53_force_link(dev, port, false);
@@ -1631,6 +1634,13 @@ static void b53_phylink_mac_link_up(struct phylink_config *config,
 	if (mode == MLO_AN_PHY) {
 		/* Re-negotiate EEE if it was enabled already */
 		p->eee_enabled = b53_eee_init(ds, port, phydev);
+
+		if (is63xx(dev) && in_range(port, B53_63XX_RGMII0, 4)) {
+			b53_force_port_config(dev, port, speed, duplex,
+					      tx_pause, rx_pause);
+			b53_force_link(dev, port, true);
+		}
+
 		return;
 	}