Merge branch 'net-phy-add-open-alliance-tc14-10base-t1s-phy-cable-diagnostic-support'

Parthiban Veerasooran says:

====================
net: phy: Add Open Alliance TC14 10Base-T1S PHY cable diagnostic support

This patch series adds Open Alliance TC14 (OATC14) 10BASE-T1S cable
diagnostic feature support to the Linux kernel PHY subsystem and enable
this feature for Microchip LAN867x Rev.D0 PHYs. These patches provide
standardized cable test functionality for 10BASE-T1S Ethernet PHYs,
allowing users to perform cable diagnostics via ethtool.

Patch Summary:
1. add OATC14 10BASE-T1S PHY cable diagnostic support
	- Implements support for the OATC14 cable diagnostic feature in
	  Clause 45 PHYs.
	- Adds functions to start a cable test and retrieve its status,
	  mapping hardware results to ethtool codes.
	- Exports these functions for use by PHY drivers.
	- Open Alliance TC14 10BASE-T1S Advanced Diagnostic PHY Features.
	  https://opensig.org/wp-content/uploads/2025/06/OPEN_Alliance_10BASE-T1S_Advanced_PHY_features_for-automotive_Ethernet_V2.1b.pdf

2. add cable diagnostic support for LAN867x Rev.D0
	- Integrates the generic OATC14 cable test functions into the
	  Microchip LAN867x Rev.D0 PHY driver.
	- Enables ethtool cable diagnostics for this PHY, improving
	  troubleshooting and maintenance.
====================

Link: https://patch.msgid.link/20251105051213.50443-1-parthiban.veerasooran@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>