Simplify the initialization of adapters by pulling all card specific
initialization to the card specific modules.
Update comments and fix formating.
Pass struct ahc_data*'s to functions instead of unit numbers.
Take advantage of the quad word alignment of SCB fields.
Adapt to new sequencer changes:
1) Waiting scb list no longer has a tail.
2) Fill the message buffer as appropriate during a parity error.
3) Count all of the SGs involved in a residual instead of just
the current one.
The reset/abort code still needs a lot of work.
Reviewed by: David Greenman <davidg@FreeBSd.org>