CONFIG_S3C2440_CPUFREQ is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

S3C2440/S3C2442 CPU Frequency scaling support

modulename: cpufreq-s3c2440.ko

and/or

s3c2440-cpufreq.ko

configname: CONFIG_S3C2440_CPUFREQ

Linux Kernel Configuration
└─>S3C2440/S3C2442 CPU Frequency scaling support
In linux kernel since version 2.6.32 (release Date: 2009-12-02)  
CPU Frequency scaling support for S3C2440 and S3C2442 SoC CPUs.

source code:
arch/arm/plat-s3c24xx/s3c2440-cpufreq.c