[arch] code format
<pb_type name="io[outpad_registered].ff[dffrn].dffrn" physical_pb_type_name="io[physical].ff" mode_bits="1">
<port name="RN" physical_mode_port="R"/>
</pb_type>
-
<!-- End physical pb_type binding in complex block IO -->
<!-- physical pb_type binding in complex block CLB -->
<!-- physical mode will be the default mode if not specified -->
