cfg80211: Save the regulatory domain when setting custom regulatory

When custom regulatory was set, only the channels setting was updated, but
the regulatory domain was not saved. Fix it by saving it.
Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20201129172929.290fa5c5568a.Ic5732aa64de6ee97ae3578bd5779fc723ba489d1@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/reg.c

@@ -2547,6 +2547,7 @@ static void handle_band_custom(struct wiphy *wiphy,
 void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
 				   const struct ieee80211_regdomain *regd)
 {
+	const struct ieee80211_regdomain *new_regd, *tmp;
 	enum nl80211_band band;
 	unsigned int bands_set = 0;
 
@@ -2566,6 +2567,13 @@ void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
 	 * on your device's supported bands.
 	 */
 	WARN_ON(!bands_set);
+	new_regd = reg_copy_regd(regd);
+	if (IS_ERR(new_regd))
+		return;
+
+	tmp = get_wiphy_regdom(wiphy);
+	rcu_assign_pointer(wiphy->regd, new_regd);
+	rcu_free_regdom(tmp);
 }
 EXPORT_SYMBOL(wiphy_apply_custom_regulatory);