Due to 32k clock jitter, tsadc will wrongly report a very
high temperature, that is a temperature-jump. This may lead
to an abnormal OS reboot. A filter function is added to
predict the true temperature.
Change-Id: I5b5641efe8e64b4058a604f274350b1e94584fa6
Signed-off-by: Rocky Hao <rocky.hao@rock-chips.com>