Thermal: Refactor thermal.h file

This patch rearranges the code in thermal.h file,
in the following order, so that it is easy to
read/maintain.
1. All #defines
2. All enums
3. All fops structures
4. All device structures
5. All function declarations

Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>