CONFIG_WANT_DEVICE_TREE is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc
default or selected kernelversion does not have config value CONFIG_WANT_DEVICE_TREE.
Result is shown for kernelversion 5.13-rc2

CONFIG_WANT_DEVICE_TREE (not configurable)

configname: CONFIG_WANT_DEVICE_TREE

Linux/PowerPC Kernel Configuration
└─>Kernel options
└─>WANT_DEVICE_TREE
In linux kernel since version 2.6.23 (release Date: 2007-10-09)  
is depended by
CONFIG_PPC_82xx