drm/amd/display: expose dentist_get_divider_from_did

expose this functions for future use.

Signed-off-by: Nevenko Stupar <Nevenko.Stupar@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>