boot loader serial console speed to 9600

[Stefan Parvu]

So here are the final comments on this:

1. Disable entire serial console, as documented here [1]

   echo 'hw.fdt.console="NO"' >> /boot/loader.conf.local

BTW the man page of loader.conf or loader must sy about this undocumented 
variable setting. 


2. Set a lower speed of the serial console from 115200 to 9600 for example

uboot config.txt
init_uart_baud=9600


It would be nice whoever wrote this part to properly document these such way this is not
a mission impossible to find. I will test in coming days these things to see if they actually 
work. 

Thanks Ian for tips and support

Stefan