drm/amd/pm: initial feature_enabled/feature_support bitmap for vangogh

VanGogh supports feature mask checking which exposed by smu firmware. It
has to initial at first, otherwise, all SMU_FEATURE_xxx masks are
invalid.

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>