net: dsa: microchip: add WoL support for KSZ87xx family

net: dsa: microchip: add WoL support for KSZ87xx family

Add WoL support for KSZ87xx family of switches. This code was tested
with a KSZ8794 chip.

Implement ksz_common usage of the new device-tree property
'microchip,pme-active-high'.

Make use of the now generalized ksz_common WoL functions, adding an
additional interrupt register write for KSZ87xx. Add helper functions
to convert from PME (port) read/writes to indirect register
read/writes in the dedicated ksz8795 sources.  Add initial
configuration during (port) setup as per KSZ9477.

Signed-off-by: Pieter Van Trappen <pieter.van.trappen@cern.ch>
Acked-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Link: https://patch.msgid.link/20240813142750.772781-5-vtpieter@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>