net: mdio: Rework scanning of bus ready for quirks

Some C22 PHYs do bad things when there are C45 transactions on the
bus. In order to handle this, the bus needs to be scanned first for
C22 at all addresses, and then C45 scanned for all addresses.

The Marvell pxa168 driver scans a specific address on the bus to find
its PHY. This is a C22 only device, so update it to use the c22
helper.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>