[coreboot] NULL pointer dereference in search_bus_device()

[Myles Watson]

> > I'd guess that it's left over from another era, but I'm not sure.  Is
> > there another use for subtractive resources?
> 
> Well in general I think port 80 is good example of subtractive resource
> decoding.
I agree.

What I meant was... When should we declare subtractive resources in
coreboot?  Do we ever need them to be allocated, searched for, etc.?

Because they're subtractive, they should just work, right?

Thanks,
Myles