UBI: Add some asserts to ubi_attach_fastmap()

Add more paranioa asserts to make it easier to detect
implementation errors.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

drivers/mtd/ubi/fastmap.c

@@ -826,6 +826,10 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list)
 		list_move_tail(&tmp_aeb->u.list, &ai->free);
 
+	ubi_assert(list_empty(&used));
+	ubi_assert(list_empty(&eba_orphans));
+	ubi_assert(list_empty(&free));
+
 	/*
 	 * If fastmap is leaking PEBs (must not happen), raise a
 	 * fat warning and fall back to scanning mode.