BACKPORT: thermal/drivers/hisi: Put platform code together

Reorganize the code for next patches by moving the functions upper in
the file which will prevent a forward declaration. There is no functional
change here.

Change-Id: I3eb1665e91bf768a2536653a29699db1460b4643
Signed-off-by: Kevin Wangtao <kevin.wangtao@linaro.org>
Tested-by: Daniel Lezcano <daniel.lezcano@linaro.org> # hikey6220
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
(cherry picked from commit a0678da82ca01771db57f53bfb7f0a5a7494900e)
Signed-off-by: Kevin Wangtao <kevin.wangtao@hisilicon.com>