tty: n_gsm: remove obsolete mknod doc example

	daemon(0,0);

	pause();

4. create the devices corresponding to the "virtual" serial ports (take care,

   each modem has its configuration and some DLC have dedicated functions,

   for example GPS), starting with minor 1 (DLC0 is reserved for the management

   of the mux)::

     MAJOR=`cat /proc/devices |grep gsmtty | awk '{print $1}`

     for i in `seq 1 4`; do

	mknod /dev/ttygsm$i c $MAJOR $i

     done

5. use these devices as plain serial ports.

4. use these devices as plain serial ports.

   for example, it's possible:

   - and to use gnokii to send / receive SMS on ttygsm1

   - to use ppp to establish a datalink on ttygsm2

6. first close all virtual ports before closing the physical port.

5. first close all virtual ports before closing the physical port.

   Note that after closing the physical port the modem is still in multiplexing

   mode. This may prevent a successful re-opening of the port later. To avoid