net: phy: realtek: fix EEE advertisement write on the internal PHY MMD path

net: phy: realtek: fix EEE advertisement write on the internal PHY MMD path

In rtlgen_write_mmd(), the MDIO_AN_EEE_ADV case swaps the arguments to
rtlgen_write_vend2(): it passes the MMD register number as the OCP address
and the OCP address constant as the value. The caller's value is discarded
and the write lands on the wrong register, so the EEE advertisement cannot
be configured on the affected PHYs.

Mirror rtlgen_read_mmd() and write the value to RTL_MDIO_AN_EEE_ADV.

Fixes: da681ed73fb9 ("net: phy: realtek: improve mmd register access for internal PHY's")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>
Link: https://patch.msgid.link/20260806134716.3511821-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>