net: ethernet: mtk_eth_soc: add NETSYS_V3 version support

Introduce NETSYS_V3 chipset version support.
This is a preliminary patch to introduce support for MT7988 SoC.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/0db2260910755d76fa48e303b9f9bdf4e5a82340.1690246066.git.daniel@makrotopia.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>