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

Support for Sibyte BCM91125E-Rhone

configname: CONFIG_SIBYTE_RHONE

System type
└─>Support for Sibyte BCM91125E-Rhone
In linux kernel since version 2.6.12  

depends
CONFIG_EXPERIMENTAL