trim down the qemu kernel config

just retain the options we need to pass the tests

modules/wlan.nix

@@ -0,0 +1,20 @@
+{ lib, pkgs, config, ...}:
+let
+  inherit (lib) mkEnableOption mkOption types isDerivation hasAttr ;
+  inherit (pkgs.pseudofile) dir symlink;
+  inherit (pkgs) busybox;
+
+in {
+  config = {
+    kernel = rec {
+      config = {
+        CFG80211= "y";
+        MAC80211= "y";
+        MAC80211_MESH= "y";
+        RFKILL= "y";
+        WLAN = "y";
+      };
+      checkedConfig = config;
+    };
+  };
+}