Some virtual machines errorneously expose null PCI device function
on PIIX4 chipset where an USB controller should normally reside.
Windows pci.sys driver does not enumerate these devices.
Affected virtual machines:
- Connectix Virtual PC 5.1.370
- Connectix Virtual PC 5.2.418
- Microsoft Virtual PC 2004 SP1 (5.3.582.27)
- Microsoft Virtual PC 2007 SP1 (6.0.156.0)
Non-affected virtual machines:
- Connectix Virtual PC 4.0
- Microsoft Hyper-V
Fixes CORE-17636.
