CONFIG_MACH_IMX53_DT is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Support i.MX53 platforms from device tree

modulename: imx53-dt.ko

configname: CONFIG_MACH_IMX53_DT

Linux Kernel Configuration
└─>Support i.MX53 platforms from device tree
In linux kernel since version 3.3 (release Date: 2012-03-18)  
Include support for Freescale i.MX53 based platforms
using the device tree for discovery

source code:
arch/arm/mach-imx/imx53-dt.c