hwmon: (max6642) Rename temp_fault sysfs attribute to temp2_fault

The temp_fault sysfs attribute is wrong, it should be temp2_fault instead.

Reported-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Per Dalen <per.dalen@appeartv.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>