[posix] avoid compiler warning on use of strncpy (#6653)
[posix] avoid compiler warning on use of strncpy (#6653)


srickardti/openthread,srickardti/openthread,abtink/openthread,srickardti/openthread,openthread/openthread,abtink/openthread,jwhui/openthread,jwhui/openthread,openthread/openthread,abtink/openthread,jwhui/openthread,srickardti/openthread,jwhui/openthread,openthread/openthread,openthread/openthread,abtink/openthread