Add support for programming the DCN3.1 OPTC (Output Timing Controller)

HW Blocks:

    +--------+
    |  MPC   |
    +--------+
        |
        v
    +-------+
    |  OPP  |
    +-------+
        |
        v
    +--------+
    |  OPTC  |
    +--------+
        |
        v
    +--------+       +--------+
    |  DIO   |       |  DCCG  |
    +--------+       +--------+

There are no changes to OPP or MPC for DCN3.1, so the diagram will
include them in this patch.
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>