drm/amdgpu: enable VCN DPG for GC IP v11.0.4

Enable VCN Dynamic Power Gating control for GC IP v11.0.4.

Signed-off-by: Saleemkhan Jamadar <saleemkhan.jamadar@amd.com>
Reviewed-by: Veerabadhran Gopalakrishnan <veerabadhran.gopalakrishnan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>