drm/amd/pm: don't mark all apu as true on feature mask

VHG based APU will support feature mask checking.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>