Add support to program the DCN2 OPP (Output Plane Processing)

HW Blocks:

    +-------+
    |  OPP  |
    +-------+
        |
        v
    +--------+
    |  OPTC  |
    +--------+
        |
        v
    +--------+       +--------+
    |  DIO   |       |  DCCG  |
    +--------+       +--------+
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>