According to the specifications AMD/ATI SMBus controller is very
similar to SMBus controller found in PIIX4.
Some notable differences:
o different bit for enabling/signalling regular interrupt mode
o in practice seems to support only polling mode
Thus, intpm driver is modified to support polling-only mode
and to recognize SB700 PCI ID and differences.
Tested on: SB700 and PIIX4E platforms
Reviewed by: jhb
MFC after: 2 weeks
X-Perhaps-ToDo: rename the driver to reflect its function
and supported hardware