drm/amdgpu/display: Prepare for new interfaces

why:
lut pipeline will be hooked up differently in some asics
need to add new interfaces

how:
add them

Reviewed-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Acked-by: Jasdeep Dhillon <jdhillon@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Martin <martin.leung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>