CONFIG_CPU_S3C2440 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
SAMSUNG S3C2440
modulename: s3c2440.ko
configname: CONFIG_CPU_S3C2440
Linux Kernel Configuration
└─>SAMSUNG S3C24XX SoCs Support
└─>SAMSUNG S3C2440
In linux kernel since version 2.6.12
Support for S3C2440 Samsung Mobile CPU based systems.