i2c-piix4: Fix SB700 PCI device ID

We find that SB700 and SB800 use the same SMBus device ID as SB600, which is
0x4385, instead of the already submitted 0x4395.

Besides removing the wrong SB700 device ID, add SB800 support to kernel, by
renaming the PCI_DEVICE_ID_ATI_IXP600_SMBUS into
PCI_DEVICE_ID_ATI_SBX00_SMBUS.

Signed-off-by: Shane Huang <shane.huang@amd.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>