CONFIG_ARCH_S3C2440 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
SMDK2440
modulename: mach-smdk2440.ko
configname: CONFIG_ARCH_S3C2440
Linux Kernel Configuration
└─>SAMSUNG S3C24XX SoCs Support
└─>SMDK2440
In linux kernel since version 2.6.12
Say Y here if you are using the SMDK2440.