drm/amd/powerplay: implement the interface for setting soft freq range

The APU soft freq range set by different way from DGPU, thus need implement
the function respectively base on each common SMU part.

Signed-off-by: Prike Liang <Prike.Liang@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>