Return domain, bus, slot, and function for the transport settings in
PATH_INQ requests for nvme.
Be pedantic and check the return value of resource_string_value. Given
that we've just found it, this is likely overkill, but if we can't
find the entry, better to fail safe.
Add device location wiring to the pci bus. This allows one to specify,
for example, that if there's an igb card in bus 12, slot 0, function
0, it should be assigned igb5. If there isn't, or there's one in a
different slot, normal numbering rules apply (hinted units are
skipped). Adding 'hint.igb.5.at="pci12:0:0"' or
'hint.igb.5.at="pci0:12:0:0"' to /boot/device.hints will accomplish
this. The quotes are important, and these are the only two forms that
are supported to avoid embedding a parser in the kernel.