drm/amd/display: Change how we disable pipe split

Before this change, pipe split was disabled by bumping up dpp clock
bounding box for DPM level 0 and 1, this allows validation to pass
without splitting at a lower DPM level. This change reverts this
and instead lowers display clock at DPM level 0, this forces
configurations that need pipe split at DPM level 0 to go to
DPM level 1, where they can be driven without split.
Signed-off-by: NEric Yang <Eric.Yang2@amd.com>
Reviewed-by: NTony Cheng <Tony.Cheng@amd.com>
Acked-by: NHarry Wentland <Harry.Wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.c

@@ -822,8 +822,7 @@ bool dcn_validate_bandwidth(
 	v->phyclk_per_state[0] = v->phyclkv_min0p65;
 
 	if (dc->public.debug.disable_pipe_split) {
-		v->max_dppclk[1] = v->max_dppclk_vnom0p8;
-		v->max_dppclk[0] = v->max_dppclk_vnom0p8;
+		v->max_dispclk[0] = v->max_dppclk_vmin0p65;
 	}
 
 	if (v->voltage_override == dcn_bw_v_max0p9) {