drm/amd/display: Add an option to limit max DSC target bpp per sink

[Why] Can be used for debug purposes
[How] Add max target bpp override field and related handling

Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>