wifi: mac80211: chan: chandef is non-NULL for reserved

The last caller of this with a NULL argument was related to
the non-chanctx code, so we can now remove this odd logic.
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240129194108.bad8ec1e76c8.I12287452f42c54baf75821e75491cf6d021af20a@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/chan.c

@@ -90,11 +90,11 @@ ieee80211_chanctx_reserved_chandef(struct ieee80211_local *local,
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
+	if (WARN_ON(!compat))
+		return NULL;
+
 	list_for_each_entry(link, &ctx->reserved_links,
 			    reserved_chanctx_list) {
-		if (!compat)
-			compat = &link->reserved_chandef;
-
 		compat = cfg80211_chandef_compatible(&link->reserved_chandef,
 						     compat);
 		if (!compat)