net: mdiobus: Convert to use fwnode_device_is_compatible()

Replace open coded fwnode_device_is_compatible() in the driver.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>