CONFIG_SOC_EXYNOS5420 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
SAMSUNG EXYNOS5420
modulename: clk-exynos5420.ko
configname: CONFIG_SOC_EXYNOS5420
Linux Kernel Configuration
└─>SAMSUNG EXYNOS SoCs Support
└─>SAMSUNG EXYNOS5420
In linux kernel since version 3.10 (release Date: 2013-06-30)
Enable EXYNOS5420 SoC support