default or selected kernelversion does not have config value CONFIG_UNISYS_VISORCHANNEL.
Result is shown for kernelversion 6.4.14

Unisys visorchannel driver

modulename: visorchannel.ko

configname: CONFIG_UNISYS_VISORCHANNEL

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>Unisys SPAR driver support
└─>Unisys visorchannel driver
In linux kernel since version 3.15 (release Date: 2014-06-08)  
If you say Y here, you will enable the Unisys visorchannel driver.

source code:
drivers/staging/unisys/visorchannel/