net: mdio: Demote probed message to debug print

On systems with large numbers of MDIO bus/muxes the message indicating
that a given MDIO bus has been successfully probed is repeated for as
many buses we have, which can eat up substantial boot time for no
reason, demote to a debug print.

Reported-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20220103194024.2620-1-f.fainelli@gmail.com


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