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

CONFIG_HAVE_IMX_MMDC (not configurable)

modulename: mmdc.ko

configname: CONFIG_HAVE_IMX_MMDC

Linux Kernel Configuration
└─>Freescale i.MX family
└─>HAVE_IMX_MMDC
In linux kernel since version 3.1 (release Date: 2011-10-24)  
source code:
arch/arm/mach-imx/mmdc.c
depends
CONFIG_ARCH_MXC

is depended by
CONFIG_SOC_IMX6