drm/amd/display: Add visual confirm for Idle State

[Why]
Visual Confirm would tell us if it ever
entered idle state.

[How]
Add debug option for IPS visual confirm

Reviewed-by: Ovidiu Bunea <ovidiu.bunea@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Duncan Ma <duncan.ma@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>