net: phy: microchip_t1: Cable Diagnostics for lan887x

Add support for cable diagnostics in lan887x PHY.
Using this we can diagnose connected/open/short wires and
also length where cable fault is occurred.

Signed-off-by: Divya Koppera <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: Divya-Koppera