r8169: set EEE speed down ratio to 1

r8169: set EEE speed down ratio to 1

EEE speed down means speed down MAC MCU clock. It is not from spec.
It is kind of Realtek specific power saving feature. But enable it
may cause some issues, like packet drop or interrupt loss. Different
hardware may have different issues.

EEE speed down ratio (mac ocp 0xe056[7:4]) is used to set EEE speed
down rate. The larger this value is, the more power can save. But it
actually save less power then we expected. And, as mentioned above,
will impact compatibility. So set it to 1 (mac ocp 0xe056[7:4] = 0)
, which means not to speed down, to improve compatibility.

Signed-off-by: ChunHao Lin <hau@realtek.com>
Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://patch.msgid.link/20250918023425.3463-1-hau@realtek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>