CONFIG_ARCH_S3C64XX is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Samsung S3C64XX

configname: CONFIG_ARCH_S3C64XX

Linux Kernel Configuration
└─>Samsung S3C64XX
In linux kernel since version 2.6.29 (release Date: 2009-03-23)  
Samsung S3C64XX series based systems