CONFIG_CACHE_L2X0_PMU is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

L2x0 performance monitor support

modulename: cache-l2x0-pmu.ko

configname: CONFIG_CACHE_L2X0_PMU

Linux Kernel Configuration
└─>L2x0 performance monitor support
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This option enables support for the performance monitoring features
of the L220 and PL310 outer cache controllers.

source code:
depends
CONFIG_PERF_EVENTS