[MAC80211]: implement ERP info change notifications

zd1211rw and bcm43xx are interested in being notified when ERP IE conditions
change, so that they can reprogram a register which affects how control frames
are transmitted.

This patch adds an interface similar to the one that can be found in softmac.

Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index b0af6e9..cc9999c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -788,6 +788,8 @@
 					 u8 *addr);
 int ieee80211_sta_deauthenticate(struct net_device *dev, u16 reason);
 int ieee80211_sta_disassociate(struct net_device *dev, u16 reason);
+void ieee80211_erp_info_change_notify(struct net_device *dev, u8 changes);
+void ieee80211_reset_erp_info(struct net_device *dev);
 
 /* ieee80211_iface.c */
 int ieee80211_if_add(struct net_device *dev, const char *name,