- split softc size and match/attach out from cfdriver into
a new struct cfattach.
- new "attach" directive for files.*. May specify the name of
the cfattach structure, so that devices may be easily attached
to parents with different autoconfiguration semantics.
pcibus and pci.
(2) remove the #ifdef i386 from pci.c, and provide a machine-dependent
hook (pci_md_attach_hook()) to do any machine-dependent attachment
gunk, e.g. on the i386 printing out the configuration mode (if bus 0)
(3) don't pass max device number for a given bus in, use
PCI_MAX_DEVICE_NUMBER, which can be defined on a per-machine basis.
(defaults to 32. on i386, it's 32 if pci conf mode == 1, 16 if 2.)
(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.
