{nl,cfg,mac}80211: enable the triggering of CSA frame in mesh

Allow the triggering of CSA frame using mesh interface. The
rules are more or less same with IBSS, such as not allowed to
change between the band and channel width has to be same from
the previous mode. Also, move the ieee80211_send_action_csa
to a common space so that it can be re-used by mesh interface.

Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@cozybit.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 4ebbcc6..9aad167 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1731,6 +1731,8 @@
 void ieee80211_dfs_cac_timer_work(struct work_struct *work);
 void ieee80211_dfs_cac_cancel(struct ieee80211_local *local);
 void ieee80211_dfs_radar_detected_work(struct work_struct *work);
+int ieee80211_send_action_csa(struct ieee80211_sub_if_data *sdata,
+			      struct cfg80211_csa_settings *csa_settings);
 
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline