drm/amd/display: use min disp and dpp clk debug option for dcn2

This allows to set a minimum display and dpp clock on dcn2+ HW
by adjusting clocks used for dml calculations.

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