thermal/drivers/hisi: Add the dual clusters sensors for hi3660

The code is ready to support multiple sensors on the hi3660. The DT
defines a thermal zone per cluster.

Add the little cluster sensor and let it bind with the thermal zone.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>