attach to the hostb driver instead. This means that agp can now be loaded
at runtime (in theory at least). Also, the drivers no longer have to
explicity call device_verbose() to cancel out any earlier calls to
device_quiet() by the hostb(4) driver (this shows a limitation in new-bus,
drivers really shouldn't be doing device_quiet() until they know they are
going to drive that device, i.e. in attach).
the Linux driver, since specs are unavailable. Many thanks to Adam Kirchhoff
for multiple useful testing cycles, and Ralf Wostrack for the final fix to get
it working.
PR: i386/75251
Submitted by: anholt
