disallow setting IEC location addresses for TIME, DATE, DT and TOD variables

Size of these types is not defined and depends on the implementation
(IEC 61131-3 2.3.1).

<?xml version='1.0' encoding='utf-8'?>
<BaseParams xmlns:xsd="http://www.w3.org/2001/XMLSchema" IEC_Channel="2" Name="py_ext_0"/>