it87: Overwrite broken default limits

Some IT8716F chips where seen with unreasonable defaults for low
voltage and high temperature limits. Overwrite them with sane defaults
so as to not generate meaningless alarms.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>