Rationale: move device information from code to data structures.
v2: Adapt the drivers missed in the first version.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Implement and use a common device bus state. The main side-effect is
that creating a bus and attaching it to a parent device are no longer
separate operations. For legacy code we allow a NULL parent, but that
should go away eventually.
Also tweak creation code to veriry theat a device in on the right bus.
Signed-off-by: Paul Brook <paul@codesourcery.com>