[PATCH net v3 1/2] net: dsa: mt7530: populate lpi_interfaces to fix EEE support

[Aleksei Sviridkin]

> Clashiko complains about the above:
>
> https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260827211652.63504-1-f%40lex.la
>
> @Andrew: WDYT?

The raw LPI_THRESH plumbing predates the phylink conversion: before
9cf21773f535, mt753x_set_mac_eee() wrote tx_lpi_timer straight into the
field with the same 0xFFF bound, so what ethtool showed and set on these
ports was always the register unit. This patch brings that path back and
does not change the unit. Settling it needs the MT7531 manual, and the
EINVAL-vs-clamp mismatch came with the conversion too. Both look like a
follow-up once someone can confirm the unit.