drm/amd/swsmu: correct wrong feature bit mapping

1. when smc feature bit isn't mapped,
the feature state isn't showed on sysfs node of pp_features.
2. add pp_features table title

Signed-off-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>