drm/amd/powerplay: update driver if file for sienna_cichlid

Update sienna_cichlid driver if header file to match pptable changes.

Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>