Changes:
* Add argument to patty_kiss_tnc_new(), patty_kiss_tnc_new_fd(),
a pointer to patty_kiss_tnc_info, to allow specifying baud and
flow control
* Rework patty_ax25_if_kiss_tnc_info to hold patty_kiss_tnc_info as
a hack to allow instantiating a KISS TNC-based network interface
with desired baud and flow control