HW Blocks:

                    +-----+
                    | HDA |
                    +-----+
                       |
                       |
    HPO ===============|=============
     |                 v
     |              +-----+
     |              | APG |
     v              +-----+
Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>