hwmon: Driver for Maxim MAX6697 and compatibles

Add support for MAX6581, MAX6602, MAX6622, MAX6636, MAX6689, MAX6693,
MAX6694, MAX6697, MAX6698, and MAX6699 temperature sensors

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <khali@linux-fr.org>