hwmon: (shtc1) add support for the SHTC3 sensor

Add support for the Sensirion SHTC3 humidity and temperature sensor to
the shtc1 module.

Signed-off-by: Dan Robertson <dan@dlrobertson.com>
Link: https://lore.kernel.org/r/20190905014554.21658-2-dan@dlrobertson.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>