CONFIG_PLAT_S3C64XX is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_PLAT_S3C64XX.
Result is shown for kernelversion 6.2.5

CONFIG_PLAT_S3C64XX (not configurable)

configname: CONFIG_PLAT_S3C64XX

Linux Kernel Configuration
└─>PLAT_S3C64XX
In linux kernel since version 2.6.29 (release Date: 2009-03-23)  
Base platform code for any Samsung S3C64XX device