drm/amd/amdgpu: add IH cg support on soc15 project

enable/disable IH clock gating on soc15 projects.

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>
3 files changed