CONFIG_MACH_KIRKWOOD is not available for the default architecture x86.
Result is shown for architecture arm

Marvell Kirkwood boards

modulename: kirkwood.ko

Linux Kernel Configuration
└─> Marvell EBU SoC variants
└─> Marvell Kirkwood boards

In linux kernel since version 3.10 (release Date: 2013-06-30)  

Say 'Y' here if you want your kernel to support boards based
on the Marvell Kirkwood device tree.

source code: