net: stmmac: interface switching support for ADL-N platform

The intel_config_serdes function was provided to handle interface mode
changes for the ADL-N platform.

The Modphy register lane was provided to configure the serdes when
changing interface modes.

Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
Signed-off-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>
Link: https://patch.msgid.link/20250227121522.1802832-7-yong.liang.choong@linux.intel.com


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