BACKPORT: thermal/drivers/hisi: Remove thermal data back pointer

The presence of the thermal data pointer in the sensor structure has the unique
purpose of accessing the thermal data in the interrupt handler.

The sensor pointer is passed when registering the interrupt handler, replace the
cookie by the thermal data pointer, so the back pointer is no longer needed.

Change-Id: I7b107fcbef723cc74b24aa45420ce12454d5800a
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
(cherry picked from commit 81d7cb7946f03d339244e1a822b7da246d8c79ff)
Signed-off-by: Kevin Wangtao <kevin.wangtao@hisilicon.com>