CONFIG_YAMON_DT_SHIM is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_YAMON_DT_SHIM (not configurable)

modulename: yamon-dt.ko

configname: CONFIG_YAMON_DT_SHIM

Linux Kernel Configuration
└─>YAMON_DT_SHIM
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Select this from your board if the board uses the YAMON bootloader
and you wish to include code which helps translate various
YAMON-provided environment variables into a device tree properties.

source code: