CONFIG_S3C64XX_DEV_SPI0 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_S3C64XX_DEV_SPI0 (not configurable)

configname: CONFIG_S3C64XX_DEV_SPI0

Linux Kernel Configuration
└─>S3C64XX_DEV_SPI0
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Compile in platform device definitions for S3C64XX's type
SPI controller 0