CONFIG_SOC_EXYNOS5250 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

SAMSUNG EXYNOS5250

modulename: clk-exynos5-subcmu.ko

and/or

clock-exynos5.ko

and/or

clk-exynos5250.ko

configname: CONFIG_SOC_EXYNOS5250

Linux Kernel Configuration
└─>SAMSUNG EXYNOS SoCs Support
└─>SAMSUNG EXYNOS5250
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Enable EXYNOS5250 SoC support

source code:
arch/arm/mach-exynos/clock-exynos5.c