cfg80211: export interface stopping function

This exports a new cfg80211_stop_iface() function.

This is intended for driver internal interface
combination management and channel switching.

Due to locking issues (it re-enters driver) the
call is asynchronous and uses cfg80211 event
list/worker.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/mesh.c b/net/wireless/mesh.c
index 3ddfb7c..092300b 100644
--- a/net/wireless/mesh.c
+++ b/net/wireless/mesh.c
@@ -238,8 +238,8 @@
 	return 0;
 }
 
-static int __cfg80211_leave_mesh(struct cfg80211_registered_device *rdev,
-				 struct net_device *dev)
+int __cfg80211_leave_mesh(struct cfg80211_registered_device *rdev,
+			  struct net_device *dev)
 {
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	int err;