CONFIG_S3C2412_DMA is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_S3C2412_DMA (not configurable)

modulename: dma-s3c2412.ko

and/or

dma.ko

configname: CONFIG_S3C2412_DMA

Linux Kernel Configuration
└─>S3C2412_DMA
In linux kernel since version 2.6.21 (release Date: 2007-04-25)  
Internal config node for S3C2412 DMA support

source code:
arch/arm/mach-s3c2412/dma.c

is depended by
CONFIG_CPU_S3C2412