vendor & product IDs and class information, which is printed if device
isn't found. Optionally (via "PCIVERBOSE" option) does table lookup
to try to see if it knows what the device really is (informational only...).
(pci_attach_subdev()). remove pciattach() function and the pcicd cfdriver
struct, the former because thre are a lot of attachment actions which really
are machine-dependent (perhaps even "most"), and the latter because now that
both pcimatch() and pciattach() are machine-dependent it's bad style to
declare them here and it gains nothing.