CONFIG_PPC_BESTCOMM is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

Bestcomm DMA engine support

modulename: bestcomm-core.ko

configname: CONFIG_PPC_BESTCOMM

Linux Kernel Configuration
└─>Bestcomm DMA engine support
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
BestComm is the name of the communication coprocessor found
on the Freescale MPC5200 family of processor. Its usage is
optional for some drivers (like ATA), but required for
others (like FEC).

If you want to use drivers that require DMA operations,
answer Y or M. Otherwise say N.

source code: