change these from bp->b_un.b_addr to bp->b_data, as well. This also
allows us more flexibility to experiment with other data buffer types
hung off of struct buf.
to a softc, rather than a unit number. Add a "dq_softc" member
to struct devqueue; this is a temporary measure until the
dma/controller/device callback spaghetti is untangled.
YAY! No more need for dcafastservice!
HIL: squish instances of "(void) splhil()" and "(void) spl0();".
thorpej