CONFIG_MXC_DEBUG_BOARD is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_MXC_DEBUG_BOARD.
Result is shown for kernelversion 6.9.9

Enable MXC debug board(for 3-stack)

modulename: 3ds_debugboard.ko

configname: CONFIG_MXC_DEBUG_BOARD

Linux Kernel Configuration
└─>Freescale i.MX family
└─>Enable MXC debug board(for 3-stack)
In linux kernel since version 2.6.36 (release Date: 2010-10-20)  
The debug board is an integral part of the MXC 3-stack(PDK)
platforms, it can be attached or removed from the peripheral
board. On debug board, several debug devices(ethernet, UART,
buttons, LEDs and JTAG) are implemented. Between the MCU and
these devices, a CPLD is added as a bridge which performs
data/address de-multiplexing and decode, signal level shift,
interrupt control and various board functions.

source code:
depends
CONFIG_ARCH_MXC
CONFIG_MACH_MX27_3DS or CONFIG_MACH_MX31_3DS or CONFIG_MACH_MX35_3DS