py: Fix "TypeError: 'iterator' object is not iterable", doh.

py/objgetitemiter.c

@@ -38,6 +38,7 @@ STATIC mp_obj_t it_iternext(mp_obj_t self_in) {
 STATIC const mp_obj_type_t it_type = {
     { &mp_type_type },
     .name = MP_QSTR_iterator,
+    .getiter = mp_identity,
     .iternext = it_iternext
 };