Assign pci buses for p9 and nics

- nics are assinged bus id 0x01
- virtfs have device with pci bus id 0x02
- maximum number of nics and virtfs are 31

Signed-off-by: Hiroshi Miura <miurahr@linux.com>
Merge pull request #238 from miurahr/issue236

Assign differnt pci buses for virtfs and nics