CONFIG_FA_DUMP is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

Firmware-assisted dump

modulename: opal-fadump.ko





configname: CONFIG_FA_DUMP

Linux Kernel Configuration
└─>Kernel options
└─>Firmware-assisted dump
In linux kernel since version 3.1 (release Date: 2011-10-24)  
A robust mechanism to get reliable kernel crash dump with
assistance from firmware. This approach does not use kexec,
instead firmware assists in booting the capture kernel
while preserving memory contents. Firmware-assisted dump
is meant to be a kdump replacement offering robustness and
speed not possible without system firmware assistance.

If unsure, say "y". Only special kernels like petitboot may
need to say "N" here.

source code: