CONFIG_ARCH_EXYNOS5 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

SAMSUNG EXYNOS5

modulename: mach-exynos5-dt.ko

configname: CONFIG_ARCH_EXYNOS5

Linux Kernel Configuration
└─>SAMSUNG EXYNOS SoCs Support
└─>SAMSUNG EXYNOS5
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Samsung EXYNOS5 (Cortex-A15) SoC based systems

source code: