drm/powerplay: add missing clockgating callback for tonga

Without this clockgating is not enabled.

Reviewed-by: Ken Wang <Qingqing.Wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Alex Deucher 2016-04-28 17:19:41 -04:00
commit ce90dbd9b8