drm/amd/display: Add swizzle visual confirm mode

[Why]
To support a new visual confirm mode: swizzle to show the specific
color at the screen border according to different surface swizzle mode.
Currently we only support the Linear mode with red color.

Signed-off-by: Po-Ting Chen <robin.chen@amd.com>
Acked-by: Stylon Wang <stylon.wang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>