it87: Add support for the IT8716F

The IT8716F is a Super-I/O chip with integrated hardware monitoring
functions. It is very similar to the IT8712F, so adding support to the
it87 driver was pretty straightforward. The most significant change here
is that the IT8716F has 16-bit fan speed counters, so the user no more
needs to tweak the fan clock dividers to get the best readings.

Userspace support is already in lm_sensors SVN (to be soon released
as 2.10.1.)

Thanks to Stian Oksavik, Olivier Nicolas, Prakash Punnoor and
Juergen Kilb for testing the early versions of this patch.

Thanks also to ITE for providing datasheets and answering my questions.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>