drm/amdgpu: enable VCN DPG for Renoir

This will enable indirect SRAM loading for VCN DPG mode initialization.

Signed-off-by: Thong Thai <thong.thai@amd.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Reviewed-by: Prike Liang <Prike.Liang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>