hwmon: (w83627ehf) Clean up probe function

The probe function has grown pretty large, I think it's time for some
cleanups, starting with these two simple ones:
* Move temp3/in6 check for the W83667HG later in the function, where
  it is done for all other chip types.
* Move temperature register setting to a separate function, to avoid
  code duplication.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>