drm/amd/display: fix dsc validation

Currently dsc is validated not taking the image width limitation into
mind.

This change addresses that, but due to previous design being limited
to non odm dsc validation additional sequence changes are made.

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Nikola Cornij <Nikola.Cornij@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>