CONFIG_BL_SWITCHER is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

big.LITTLE switcher support

modulename: bL_switcher.ko

configname: CONFIG_BL_SWITCHER

Linux Kernel Configuration
└─>Kernel Features
└─>big.LITTLE switcher support
In linux kernel since version 3.10 (release Date: 2013-06-30)  
The big.LITTLE "switcher" provides the core functionality to
transparently handle transition between a cluster of A15's
and a cluster of A7's in a big.LITTLE system.

source code: