CONFIG_BCM47XX_SSB is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

SSB Support for Broadcom BCM47XX

configname: CONFIG_BCM47XX_SSB

Linux Kernel Configuration
└─>SSB Support for Broadcom BCM47XX
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Add support for old Broadcom BCM47xx boards with Sonics Silicon Backplane support.

This will generate an image with support for SSB and MIPS32 R1 instruction set.