Merge branch 'net-phy-MDIO-bus-scanning-fixes'

Florian Fainelli says:

====================
net: phy: MDIO bus scanning fixes

This patch series fixes two problems with the current MDIO bus scanning
logic which was identified while moving from 4.9 to 5.4 on devices that
do rely on scanning the MDIO bus at runtime because they use pluggable
cards.

Changes in v2:

- added comment explaining the special value of -ENODEV
- added Andrew's Reviewed-by tag
====================

Signed-off-by: David S. Miller <davem@davemloft.net>