o Cut out the probed stuff. We no longer need it since newbus implicitly
checks for this (likely bt can be changed as well in this way).
o Add preliminary support for unload. Untested because aha doesn't yet
support identify and there are some interactions with PnP that I've
not yet worked out.
With this I can boot the AHA-1542CP FW F.0. All the aha resources
appear to be picked up via pnp now.