linuxptp daemon : Change default maxInspecOffset to 1500ns

[aneeshkp]

T-GM uses the MaxInSpecOffset value to determine the state change from HOLDOVER to FREERUN. By default, HoldoverTimeout is set to 14,400 seconds, LocalMaxHoldoverOffset is 1,500 ns, and MaxInSpecOffset is set to 100 ns. With this configuration, the holdover state times out in 16 minutes due to the slope increment occurring every second, reaching MaxInSpecOffset of 100ns within 16 minutes.

E810 support 4 hours of holdover and to keep this behavior consistent need to set default MaxInSpecOffset to 1500
Current

           LocalMaxHoldoverOffSet: 1500
           LocalHoldoverTimeout: 14400
          MaxInSpecOffset: 100

New

           LocalMaxHoldoverOffSet: 1500
           LocalHoldoverTimeout: 14400
          MaxInSpecOffset:  1500 

The code change is in linuxptp daemon , but requires updates in ztp repo and docs