Improving bus/resource API

[M. Warner Losh]

First, you need to do s/dwiw/dwim/g.  dwiw has little traction, but
dwim is an old lisp term.  I believe I've said this before.

I'd collect the bs{r,w}_{1,2,4,8} routines in a central place.  They
are all the same #define.  Also, there's no provision for the more
exotic variations.

Bug: There's a disconnect between the resource spec and what you've
implemented.  You're replaced the normal flags (typically RF_ACTIVE)
with non-normal ones (0).

You've also encoded the size and offsets of struct resource into every
driver.  Given the new breakup of this, it might not be too bad.
However, that has caused us problems in the past.  This is my primary
issue with these patches.

Warner