cfg80211: Acquire wiphy mutex on regulatory work

The function cfg80211_reg_can_beacon_relax() expects wiphy
mutex to be held when it is being called. However, when
reg_leave_invalid_chans() is called the mutex is not held.
Fix it by acquiring the lock before calling the function.

Fixes: a05829a7 ("cfg80211: avoid holding the RTNL when calling the driver")
Signed-off-by: NIlan Peer <ilan.peer@intel.com>
Signed-off-by: NLuca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20211202152831.527686cda037.I40ad9372a47cbad53b4aae7b5a6ccc0dc3fddf8b@changeidSigned-off-by: NJohannes Berg <johannes.berg@intel.com>

net/wireless/reg.c

@@ -2359,6 +2359,7 @@ static bool reg_wdev_chan_valid(struct wiphy *wiphy, struct wireless_dev *wdev)
 	struct cfg80211_chan_def chandef = {};
 	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 	enum nl80211_iftype iftype;
+	bool ret;
 
 	wdev_lock(wdev);
 	iftype = wdev->iftype;
@@ -2408,7 +2409,11 @@ static bool reg_wdev_chan_valid(struct wiphy *wiphy, struct wireless_dev *wdev)
 	case NL80211_IFTYPE_AP:
 	case NL80211_IFTYPE_P2P_GO:
 	case NL80211_IFTYPE_ADHOC:
-		return cfg80211_reg_can_beacon_relax(wiphy, &chandef, iftype);
+		wiphy_lock(wiphy);
+		ret = cfg80211_reg_can_beacon_relax(wiphy, &chandef, iftype);
+		wiphy_unlock(wiphy);
+
+		return ret;
 	case NL80211_IFTYPE_STATION:
 	case NL80211_IFTYPE_P2P_CLIENT:
 		return cfg80211_chandef_usable(wiphy, &chandef,