CONFIG_DMA_NONCOHERENT is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_DMA_NONCOHERENT (not configurable)

modulename: dma-noncoherent.ko

configname: CONFIG_DMA_NONCOHERENT

Linux/MIPS Kernel Configuration
└─>Machine selection
└─>DMA_NONCOHERENT
In linux kernel since version 2.6.12  
source code:
arch/mips/mm/dma-noncoherent.c