drm/amdgpu/discovery: enable vcn/jpeg v4_0_4

Enable vcn/jpeg 4_0_4.

Signed-off-by: James Zhu <James.Zhu@amd.com>
Reviewed-by: Sonny Jiang <sonny.jiang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>