mac80211: refactor ieee80211_ibss_process_chanswitch()

Refactor ieee80211_ibss_process_chanswitch() to use
ieee80211_channel_switch() and avoid code duplication.

Tested by: Simon Wunderlich <sw@simonwunderlich.de>
Acked by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index adbff71..fb5dbcb 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1450,6 +1450,8 @@
 
 /* channel switch handling */
 void ieee80211_csa_finalize_work(struct work_struct *work);
+int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
+			     struct cfg80211_csa_settings *params);
 
 /* interface handling */
 int ieee80211_iface_init(void);