linux/kernel/common-config: Reenable the rfkill-input module

The default value of the RFKILL_INPUT Kconfig option depends on the
EXPERT option which was changed in 3b07356d2d.
However, disabling the rfkill-input module was unintentional and causes
some airplane mode buttons on laptops to not function [1].

[1]: https://github.com/NixOS/nixpkgs/issues/261880

pkgs/os-specific/linux/kernel/common-config.nix

@@ -296,6 +296,7 @@ let
       # At the time of writing (25-06-2023): this is only used in a "correct" way by ath drivers for initiating DFS radiation
       # for "certified devices"
       EXPERT                      = option yes; # this is needed for offering the certification option
+      RFKILL_INPUT                = option yes; # counteract an undesired effect of setting EXPERT
       CFG80211_CERTIFICATION_ONUS = option yes;
       # DFS: "Dynamic Frequency Selection" is a spectrum-sharing mechanism that allows
       # you to use certain interesting frequency when your local regulatory domain mandates it.