drm/amd/display: Add a flags union for 3dlut transformation matrix

[Why & How]
When TM is enabled with 3dlut, we apply conversion to
dcip3 in gamut remap matrix, if source area less than
dcip3. If it is bigger, we remap to bt2020. The added
flags will be used to facilitate this logic.

Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>