CONFIG_CPU_S3C2440 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_CPU_S3C2440 (not configurable)

modulename: s3c2440.ko

and/or

irq.ko

and/or

clock.ko

configname: CONFIG_CPU_S3C2440

Linux Kernel Configuration
└─>CPU_S3C2440
In linux kernel since version 2.6.12  
Support for S3C2440 Samsung Mobile CPU based systems.

source code:
/arch/arm/mach-s3c2440/


is selected by
CONFIG_CPU_ARM920T

is depended by
CONFIG_SMDK2440_CPU2440