ath: add common function ath_is_mybeacon

this function is used by most ath driver, so it can be moved here.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath.h b/drivers/net/wireless/ath/ath.h
index e0ba7cd..b59cfbe 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -17,6 +17,7 @@
 #ifndef ATH_H
 #define ATH_H
 
+#include <linux/etherdevice.h>
 #include <linux/skbuff.h>
 #include <linux/if_ether.h>
 #include <linux/spinlock.h>
@@ -165,6 +166,7 @@
 struct sk_buff *ath_rxbuf_alloc(struct ath_common *common,
 				u32 len,
 				gfp_t gfp_mask);
+bool ath_is_mybeacon(struct ath_common *common, struct ieee80211_hdr *hdr);
 
 void ath_hw_setbssidmask(struct ath_common *common);
 void ath_key_delete(struct ath_common *common, struct ieee80211_key_conf *key);