CONFIG_BSC9131_RDB is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

Freescale BSC9131RDB

modulename: bsc913x_rdb.ko

configname: CONFIG_BSC9131_RDB

Linux Kernel Configuration
└─>Freescale Book-E Machine Type
└─>Freescale BSC9131RDB
In linux kernel since version 3.1 (release Date: 2011-10-24)  
This option enables support for the Freescale BSC9131RDB board.
The BSC9131 is a heterogeneous SoC containing an e500v2 powerpc and a
StarCore SC3850 DSP
Manufacturer : Freescale Semiconductor, Inc

source code:
arch/powerpc/platforms/85xx/bsc913x_rdb.c