CONFIG_EXYNOS_ATAGS is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_EXYNOS_ATAGS.
Result is shown for kernelversion 6.2.5

ATAGS based boot for EXYNOS (deprecated)

configname: CONFIG_EXYNOS_ATAGS

Linux Kernel Configuration
└─>SAMSUNG EXYNOS SoCs Support
└─>ATAGS based boot for EXYNOS (deprecated)
In linux kernel since version 3.1 (release Date: 2011-10-24)  
The EXYNOS platform is moving towards being completely probed
through device tree. This enables support for board files using
the traditional ATAGS boot format.
Note that this option is not available for multiplatform builds.