mac80211: fix some missing includes

Some header files in mac80211 don't include all the
header files they require, fix that.

Signed-off-by: Zhao, Gang <gamerh2o@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/debugfs_netdev.h b/net/mac80211/debugfs_netdev.h
index 79025e7..9f5501a 100644
--- a/net/mac80211/debugfs_netdev.h
+++ b/net/mac80211/debugfs_netdev.h
@@ -3,6 +3,8 @@
 #ifndef __IEEE80211_DEBUGFS_NETDEV_H
 #define __IEEE80211_DEBUGFS_NETDEV_H
 
+#include "ieee80211_i.h"
+
 #ifdef CONFIG_MAC80211_DEBUGFS
 void ieee80211_debugfs_add_netdev(struct ieee80211_sub_if_data *sdata);
 void ieee80211_debugfs_remove_netdev(struct ieee80211_sub_if_data *sdata);