MFC: r260064

- Probe with BUS_PROBE_DEFAULT instead of 0.
- Nuke code setting PCI_POWERSTATE_D0; pci(4) already does that for type 0
  devices.
- There's no need to keep track of resource IDs.
- Quiesce the interrupt before actually detaching.
- Use DEVMETHOD_END.
- Use NULL instead of 0 for pointers.