default or selected kernelversion does not have config value CONFIG_NL80211.
Result is shown for kernelversion 5.3.7

nl80211 new netlink interface support

configname: CONFIG_NL80211

Linux Kernel Configuration
└─>Networking support
└─>Wireless
└─>nl80211 new netlink interface support
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
This option turns on the new netlink interface
(nl80211) support in cfg80211.

If =n, drivers using mac80211 will be configured via
wireless extension support provided by that subsystem.

If unsure, say Y.