drm/i915: ensure context objects are bound to the global gtt

This way round we don't introduce and ugly layering violations and use
the interface as I planned to use it.
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_context.c

@@ -358,6 +358,9 @@ static int do_switch(struct drm_i915_gem_object *from_obj,
 	if (ret)
 		return ret;
 
+	if (!to->obj->has_global_gtt_mapping)
+		i915_gem_gtt_bind_object(to->obj, to->obj->cache_level);
+
 	if (!to->is_initialized || is_default_context(to))
 		hw_flags |= MI_RESTORE_INHIBIT;
 	else if (WARN_ON_ONCE(from_obj == to->obj)) /* not yet expected */