drm: fix leak of device mappings since multi-master changes.

Device maps now contain a link to the master that created them, so
when cleaning up the master, remove any maps that are connected to it.
Also delete any remaining maps at driver unload time.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index 5ca132a..46bb923 100644
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -118,12 +118,20 @@
 	struct drm_master *master = container_of(kref, struct drm_master, refcount);
 	struct drm_magic_entry *pt, *next;
 	struct drm_device *dev = master->minor->dev;
+	struct drm_map_list *r_list, *list_temp;
 
 	list_del(&master->head);
 
 	if (dev->driver->master_destroy)
 		dev->driver->master_destroy(dev, master);
 
+	list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head) {
+		if (r_list->master == master) {
+			drm_rmmap_locked(dev, r_list->map);
+			r_list = NULL;
+		}
+	}
+
 	if (master->unique) {
 		drm_free(master->unique, master->unique_size, DRM_MEM_DRIVER);
 		master->unique = NULL;