CONFIG_SOC_EXYNOS4212 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Samsung Exynos4212

configname: CONFIG_SOC_EXYNOS4212

Linux Kernel Configuration
└─>Samsung Exynos
└─>Samsung Exynos4212
In linux kernel since version 3.1 (release Date: 2011-10-24)