drm/amd/display: Add gfx12 modifiers

Expose linear modifier definitions for use with DCN401

Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>