Generalize KSZ9477 WoL functions at ksz_common. Move dedicated registers
and generic masks to existing structures & defines for that purpose.

Introduction of PME (port) read/write helper functions, which happen
to be the generic read/write for KSZ9477 but not for the incoming
KSZ87xx patch.
Signed-off-by: Pieter Van Trappen <pieter.van.trappen@cern.ch>
Acked-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Link: https://patch.msgid.link/20240813142750.772781-4-vtpieter@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>