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

CONFIG_SIBYTE_STANDALONE (not configurable)

modulename: prom.ko

configname: CONFIG_SIBYTE_STANDALONE

Linux/MIPS Kernel Configuration
└─>Machine selection
└─>SIBYTE_STANDALONE
In linux kernel since version 2.6.12  
source code:
arch/mips/sibyte/sb1250/prom.c