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

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: 967dd82ffc52 ("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>