ath9k: Cleanup ath_vif struct

Remove unused bssid from ath_vif and set av_bslot on beacon
alloc/return.

Signed-off-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index f688527..dfd1b98 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -323,6 +323,7 @@
 		if (avp->av_bslot != -1) {
 			sc->beacon.bslot[avp->av_bslot] = NULL;
 			sc->nbcnvifs--;
+			avp->av_bslot = -1;
 		}
 
 		bf = avp->av_bcbuf;