hwmon: (f71882fg) Prepare for adding F8000 support

This patch is a preparation patch for adding F8000 support to the f71882fg
driver. If you look at the register addresses and esp, the bits used for
the temperature channels, then you will notice that it appears that they
start at 1 in a system meant to start at 0. As the F8000 actually uses the 0
addresses and bits, this patch changes the f71882fg driver to take 4
temperatures numbered 0-3 in to account, using 1-3 in this new scheme for
the temperatures actually present in the F718x2FG.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>