drm/sis: track user->memblock mapping with idr

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/via/via_map.c b/drivers/gpu/drm/via/via_map.c
index b09f659..fa5afbc 100644
--- a/drivers/gpu/drm/via/via_map.c
+++ b/drivers/gpu/drm/via/via_map.c
@@ -126,6 +126,8 @@
 	drm_via_private_t *dev_priv = dev->dev_private;
 
 	drm_sman_takedown(&dev_priv->sman);
+	idr_remove_all(&dev_priv->object_idr);
+	idr_destroy(&dev_priv->object_idr);
 
 	kfree(dev_priv);