drm/amd/powerplay: move get_thermal_temperature_range to ppt funcs

The thermal policy could be ASIC specific ones and depends on structures
in pptable. As a result, get_thermal_temperature_range should be implemented
as ppt funcs instead of smu funcs

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>