drm/amd/powerplay: enable DCEFCLK dpm support

Enabale DCEFCLK dpm on navi10

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