CONFIG_MACH_KIRKWOOD is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
Marvell Kirkwood boards
modulename: kirkwood.ko
configname: CONFIG_MACH_KIRKWOOD
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.
on the Marvell Kirkwood device tree.