Revert "drm/amdgpu: use direct loading on renoir vcn for the moment"

This reverts commit 444a0fea.

We are ready to enable it now.

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