cfg80211: make wdev_list accessible to drivers

There's no harm in having drivers read the list, since they can
use RCU protection or RTNL locking; allow this to not require
each and every driver to also implement its own bookkeeping.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/reg.c

@@ -1639,7 +1639,7 @@ static void reg_leave_invalid_chans(struct wiphy *wiphy)
 
 	ASSERT_RTNL();
 
-	list_for_each_entry(wdev, &rdev->wdev_list, list)
+	list_for_each_entry(wdev, &rdev->wiphy.wdev_list, list)
 		if (!reg_wdev_chan_valid(wiphy, wdev))
 			cfg80211_leave(rdev, wdev);
 }