CONFIG_CACHE_L2X0 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_CACHE_L2X0 (not configurable)

modulename: cache-l2x0.ko

and/or

l2x0.ko

configname: CONFIG_CACHE_L2X0

Linux Kernel Configuration
└─>CACHE_L2X0
In linux kernel since version 2.6.21 (release Date: 2007-04-25)  
source code:
arch/arm/mm/cache-l2x0.c