CONFIG_MACH_S3C2413 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_MACH_S3C2413 (not configurable)

configname: CONFIG_MACH_S3C2413

Linux Kernel Configuration
└─>S3C24XX Implementations
└─>MACH_S3C2413
In linux kernel since version 2.6.18 (release Date: 2006-09-19)  
Internal node for S3C2413 verison of SMDK2413, so that
machine_is_s3c2413() will work when MACH_SMDK2413 is
selected