vendor-specific device ids across vendors.
- Include the revision in the dc_devs[] array instead of special casing
the revid handling in dc_devtype().
- Use PCI bus accessors to read registers instead of pci_read_config()
where possible.
- Use an 8-bit write to update the latency timer.
- Use PCIR_xxx constants and remove unused DC_xxx related to standard
PCI config registers.
MFC after: 1 week