drm/radeon: enable mgcg on SI
drm/radeon: enable mgcg on SI

Now that the CP is no longer reset and cg is properly
disabled in when appropriate in the dpm code we can
now enable mgcg (medium grained clockgating).

Signed-off-by: Alex Deucher <08dc22c6156113f2deff178e35e3ed9b24d6af9e@amd.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs