CONFIG_SOC_EXYNOS3250 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Samsung Exynos3250

configname: CONFIG_SOC_EXYNOS3250

Linux Kernel Configuration
└─>Samsung Exynos
└─>Samsung Exynos3250
In linux kernel since version 3.10 (release Date: 2013-06-30)