drm/amd/pm: correct the way for checking custom OD settings

`FeatureCtrlMask` should not be included in those settings interested.

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