misc: keba: Add LAN9252 driver

KEBA CP500 devices use the LAN9252 controller for EtherCAT
communication. For a stable Ethernet link the PHY registers of the
controller need to be configured correctly. This driver configures these
PHY registers as required.

Signed-off-by: Gerhard Engleder <eg@keba.com>
Link: https://lore.kernel.org/r/20241011191257.19702-5-gerhard@engleder-embedded.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>