CONFIG_MACH_EXYNOS4_DT is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Samsung Exynos4 Machine using device tree

modulename: mach-exynos4-dt.ko

configname: CONFIG_MACH_EXYNOS4_DT

Linux Kernel Configuration
└─>SAMSUNG EXYNOS SoCs Support
└─>Samsung Exynos4 Machine using device tree
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Machine support for Samsung Exynos4 machine with device tree enabled.
Select this if a fdt blob is available for the Exynos4 SoC based board.
Note: This is under development and not all peripherals can be supported
with this machine file.

source code:
arch/arm/mach-exynos/mach-exynos4-dt.c