- 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.
of bwtwo, cgfour, cgsix, and cgeight. Includes support for attaching
the overlay plane of the cgfour and cgeight as a bwtwo instance (a'la
SunOS).
P4 register descriptions, cgfour driver, and cgeight driver partially
derived from OpenBSD.
This code may still need polishing.
