drm/amd/display: Visual Confirm Bar Height Adjust

[What]
This change allows adjustment to the Visual Confirm
height border.

[Why]
Aids debugging and testing

[How]
Use the existing infrastructure to implement logic to
draw borders

Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Harry VanZyllDeJong <hvanzyll@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>