thermal/drivers/hisi: Convert long to int

There is no point to specify the temperature as long variable, the int is
enough.

Replace all long variables to int, so making the code consistent.

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