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

Sibyte BCM91250C2-LittleSur

configname: CONFIG_SIBYTE_LITTLESUR

System type
└─>Sibyte BCM91250C2-LittleSur
In linux kernel since version 2.6.12  

depends
CONFIG_EXPERIMENTAL