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

Flattened Device Tree support

configname: CONFIG_USE_OF

Linux Kernel Configuration
└─>Boot options
└─>Flattened Device Tree support
In linux kernel since version 2.6.37 (release Date: 2011-01-04)  
Include support for flattened device tree machine descriptions.

selects
CONFIG_IRQ_DOMAIN
CONFIG_OF