[ozone] Remove unneeded workaround for disabling display controllers.

ui/ozone/platform/drm/gpu/screen_manager.cc

Index: ui/ozone/platform/drm/gpu/screen_manager.cc
diff --git a/ui/ozone/platform/drm/gpu/screen_manager.cc b/ui/ozone/platform/drm/gpu/screen_manager.cc
index 3dc6c4fcdda0bad291b974063032fca94f5a3897..120de8c33f3a06f8a39424af55a335de0bb4d94f 100644
--- a/ui/ozone/platform/drm/gpu/screen_manager.cc
+++ b/ui/ozone/platform/drm/gpu/screen_manager.cc
@@ -182,13 +182,6 @@ bool ScreenManager::DisableDisplayController(
       controllers_.push_back(controller);
     }
 
-    if (!controller->IsDisabled()) {
-      // Workaround for driver bug that does not release the buffer on null
-      // modeset.
-      ModesetDisplayController(controller, controller->origin(),
-                               controller->get_mode(), false);
-    }
-
     controller->Disable();
     UpdateControllerToWindowMapping();
     return true;