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.
This is for sure the most overkill hardware I've ever seen! For example,
it needs the VAX page tables so that it can access all data structures
and mbufs in virtual memory! It will be a real challenge to make this
device work on mips and Alpha systems :-)
