mac80211: consolidate TIM handling code

This consolidates all TIM handling code to avoid re-introducing
errors with the bitmap/set_tim order and to reduce code. While
reading the code I noticed a possible problem so I also added
a comment about that.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index f3d9f87..4099ece 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -244,7 +244,9 @@
 void sta_info_init(struct ieee80211_local *local);
 int sta_info_start(struct ieee80211_local *local);
 void sta_info_stop(struct ieee80211_local *local);
-void sta_info_remove_aid_ptr(struct sta_info *sta);
 void sta_info_flush(struct ieee80211_local *local, struct net_device *dev);
 
+void sta_info_set_tim_bit(struct sta_info *sta);
+void sta_info_clear_tim_bit(struct sta_info *sta);
+
 #endif /* STA_INFO_H */