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

Support for Sibyte BCM91250C2-LittleSur

configname: CONFIG_SIBYTE_LITTLESUR

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