drm/amd/display: Fix USB4 Aux via DMUB terminate unexpectedly

[Why]
Condition variable sometimes terminated unexpectedly

[How]
Use wait_for_completion_timeout to avoid unexpected termination of CV

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>