drm/amd/display: Promote DC to 3.2.389

drm/amd/display: Promote DC to 3.2.389

This DC patchset brings improvements in multiple areas. In summary, we have:

* Fixes on EDID 8K parsing, cursor mode, backlight, OLED/VABC, and HDR to SDR
* Improvements on DCN42 clocking, det allocation, and power gating
* Greatly enhanced KUnit coverage across amdgpu_dm
* Code cleanup

Acked-by: George Zhang <george.zhang@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Taimur Hassan <Syed.Hassan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>