CONFIG_PPC_BARRIER_NOSPEC is not available for the selected architecture x86.
Result is shown for architecture powerpc

CONFIG_PPC_BARRIER_NOSPEC (not configurable)

modulename: security.ko

configname: CONFIG_PPC_BARRIER_NOSPEC

Linux Kernel Configuration
└─>PPC_BARRIER_NOSPEC
In linux kernel since version 3.10 (release Date: 2013-06-30)
source code:
arch/powerpc/kernel/security.c