Support for console on a BCM1xxx DUART serial port

configname: CONFIG_SERIAL_SB1250_DUART_CONSOLE

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>Support for console on a BCM1xxx DUART serial port
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
If you say Y here, it will be possible to use a serial port as the
system console (the system console is the device which receives all
kernel messages and warnings and which allows logins in single user
mode).

If unsure, say Y.