CONFIG_SH_DREAMCAST is not available for thedefaultarchitecture x86.
Result is shown for architecture sh

Dreamcast

modulename: dma-pvr2.ko

and/or

ops-dreamcast.ko

configname: CONFIG_SH_DREAMCAST

SuperH system type
└─>Dreamcast
In linux kernel since version 2.6.12  
Select Dreamcast if configuring for a SEGA Dreamcast.
More information at
<http://www.m17n.org/linux-sh/dreamcast/>. There is a
Dreamcast project is at <http://linuxdc.sourceforge.net/>.

source code:
/arch/sh/drivers/dma/