drm/amd/display: fix DML not calculating delivery time

[why]
Calculating DCFCLK DS time requires calculating
delivery time for luma/chroma, but this value is
not calculated in DMLv2, it was inadvertently
removed when porting DMLv2

[how]
Add the calculation back

Signed-off-by: Jun Lei <Jun.Lei@amd.com>
Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>