CONFIG_HOTPLUG is not available for thedefaultarchitecture x86.
Result is shown for architecture tile

Support for hot-pluggable devices

modulename: hotplug.ko

and/or

setup-bus.ko

configname: CONFIG_HOTPLUG

Linux Kernel Configuration
└─>Bus options
└─>Support for hot-pluggable devices
In linux kernel since version 2.6.13 (release Date: 2005-08-28)  
Say Y here if you want to plug devices into your computer while
the system is running, and be able to use them quickly. In many
cases, the devices can likewise be unplugged at any time too.
One well-known example of this is USB.

source code: