net: mdio: warn once if addr parameter is invalid in mdiobus_get_phy()

If mdiobus_get_phy() is called with an invalid addr parameter, then the
caller has a bug. Print a call trace to help identifying the caller.

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/daec3f08-6192-ba79-f74b-5beb436cab6c@gmail.com


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