net: phy: broadcom: implement .disable_autonomous_eee for BCM54xx

net: phy: broadcom: implement .disable_autonomous_eee for BCM54xx

Implement the .disable_autonomous_eee callback for the BCM54210E.

In AutogrEEEn mode the PHY manages EEE autonomously. Clearing the
AutogrEEEn enable bit in MII_BUF_CNTL_0 switches the PHY to Native
EEE mode.

Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20260406-devel-autonomous-eee-v1-2-b335e7143711@tipi-net.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>