drm/amdgpu: enable VCN4 PG and CG for VCN4_0_0

Most of the tiles can be power/clock gated.

Reviewed-by: Sonny Jiang <sonny.jiang@amd.com>
Signed-off-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>