drm/i915/dp_mst: Add missing DSC compression disabling

Add the missing DSC compression disabling step for MST streams,
similarly to how this is done for SST outputs.
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231030155843.2251023-18-imre.deak@intel.com

drivers/gpu/drm/i915/display/intel_dp_mst.c

@@ -730,6 +730,8 @@ static void intel_mst_post_disable_dp(struct intel_atomic_state *state,
 
 	intel_ddi_disable_transcoder_func(old_crtc_state);
 
+	intel_dsc_disable(old_crtc_state);
+
 	if (DISPLAY_VER(dev_priv) >= 9)
 		skl_scaler_disable(old_crtc_state);
 	else