drm/amdgpu/vcn: enable vcn4 dpg mode

Enable vcn4 dpg mode.
Signed-off-by: James Zhu <James.Zhu@amd.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/soc21.c

@@ -486,6 +486,7 @@ static int soc21_common_early_init(void *handle)
 			AMD_CG_SUPPORT_VCN_MGCG |
 			AMD_CG_SUPPORT_JPEG_MGCG;
 		adev->pg_flags = AMD_PG_SUPPORT_VCN |
+			AMD_PG_SUPPORT_VCN_DPG |
 			AMD_PG_SUPPORT_JPEG |
 			AMD_PG_SUPPORT_ATHUB |
 			AMD_PG_SUPPORT_MMHUB;