unexpected interrupts. If an interrupt is triggered and we're not
finished initializing yet, bail. If we have finished initializing,
but IFF_UP isn't set yet, drain the interrupt with ndis_intr() or
ndis_disable_intr() as appropriate, then return _without_ scheduling
ndis_intrtask().
In kern_ndis.c:ndis_load_driver() only relocate/dynalink a given driver
image once. Trying to relocate an image that's already been relocated
will trash the image. We poison a part of the image header that we
don't otherwise need with a magic value to indicate it's already been
fixed up. This fixes the case where there are multiple units of the
same kind of device.