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

CONFIG_PLAT_SAMSUNG (not configurable)

configname: CONFIG_PLAT_SAMSUNG

Linux Kernel Configuration
└─>PLAT_SAMSUNG
In linux kernel since version 2.6.33 (release Date: 2010-02-24)  
Base platform code for all Samsung SoC based systems

selects
CONFIG_GENERIC_IRQ_CHIP
CONFIG_NO_IOPORT_MAP
CONFIG_SOC_SAMSUNG


is selected by
CONFIG_S3C24XX_PWM

is depended by
CONFIG_ARCH_S3C64XX