mac80211: compute chanctx refcount on-the-fly

It doesn't make much sense to store refcount in
the chanctx structure. One still needs to hold
chanctx_mtx to get the value safely. Besides,
refcount isn't on performance critical paths.

This will make implementing chanctx reservation
refcounting a little easier.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 9620d4f..4d15a15 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -3251,7 +3251,7 @@
 
 	/* don't handle for multi-VIF cases */
 	chanctx = container_of(conf, struct ieee80211_chanctx, conf);
-	if (chanctx->refcount > 1) {
+	if (ieee80211_chanctx_refcount(local, chanctx) > 1) {
 		mutex_unlock(&local->chanctx_mtx);
 		return -EBUSY;
 	}