drm/i915: Use common LRU inactive vma bumping for unpin_from_display

Now that i915_gem_object_bump_inactive_ggtt() exists, also make use of
it for the LRU bumping from i915_gem_object_unpin_from_display()

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170119192659.31789-2-chris@chris-wilson.co.uk
Reviewed-by: Jonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/i915_gem.c

@@ -3556,8 +3556,7 @@ i915_gem_object_unpin_from_display_plane(struct i915_vma *vma)
 		vma->display_alignment = I915_GTT_MIN_ALIGNMENT;
 
 	/* Bump the LRU to try and avoid premature eviction whilst flipping  */
-	if (!i915_vma_is_active(vma))
-		list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
+	i915_gem_object_bump_inactive_ggtt(vma->obj);
 
 	i915_vma_unpin(vma);
 }