net: phy: micrel: Add Fast link failure support for lan8842

net: phy: micrel: Add Fast link failure support for lan8842

Add support for fast link failure for lan8842, when this is enabled the
PHY will detect link down immediately (~1ms). The disadvantage of this
is that also small instability might be reported as link down.
Therefore add this feature as a tunable configuration and the user will
know when to enable or not. By default it is not enabled.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250917104630.3931969-1-horatiu.vultur@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>