o Assign sc->an_dev in an_probe() (which isn't really a probe function in
the standard newbus sense) as we may need it for printing errors.
o Use device_printf() rather than if_printf() in an_reset() - this is
called from an_probe() long before the ifp structure is initialised
in an_attach().
o Initialize the ifp structure early in an_attach() as we use if_printf()
in cases where allocation of descriptors etc fails.
MFC after: 3 days