hwmon: (smsc47b397) add a new chip id (0x8c)

Added a new ID (0x8c) for the smsc47b397 hardware monitor driver.
This ID is used by HP in, at least, their dc7700 line.

Signed-off-by: Craig Kelley <namonai@gmail.com>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>