The modifications include:
- adding pps_valid_i line, indicating if the PPS input is not being re-adjusted (which may result in generation of incorrect timestamps)
- TX/RX timestamp incorrect flags: when 1, the client should discard the timestamp, as it may be broken.
- TXTSU interface change (to avoid confusion between former valid output and new incorrect output)
  * txtsu_valid_o -> txtsu_stb_o
  * txtsu_tsval_o -> txtsu_ts_value_o
  * new port      -> txtsu_ts_incorrect_o