drm/amd/display: Support for SET_CONFIG processing with DMUB

[Why]
To process SET_CONFIG transactions with DMUB using inbox1 and
outbox1 mail boxes.

[How]
1) DMUB posts SET_CONFIG reply as an Outbox1 message of type
   DMUB_OUT_CMD__SET_CONFIG_REPLY.
2) The dmub async to sync mechanism for AUX is modified to accommodate
   SET_CONFIG commands for both command issue and reply code paths.

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Jude Shih <shenshih@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>