drm/amd/display: Check minimum disp_clk and dpp_clk debug option

Our debug struct has the min_disp_clk_khz and min_dpp_clk_khz options,
which we ignore in the DCN32. This commit introduces those checks and
the necessary calculation.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Aurabindo Jayamohanan Pillai <Aurabindo.Pillai@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>