CONFIG_SBC8548 is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

Wind River SBC8548

modulename: sbc8548.ko

configname: CONFIG_SBC8548

Linux Kernel Configuration
└─>Freescale Book-E Machine Type
└─>Wind River SBC8548
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
This option enables support for the Wind River SBC8548 board

source code: