Ath5k: lock beacons

Beacons setup and config was racy with beacon send. Ensure that
ISR and reset functions see consistent state of bbuf.

Use also dev_kfree_skb_any in ath5k_txbuf_free since we call it
from atomic now.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Nick Kossifidis <mickflemm@gmail.com>
Cc: Luis R. Rodriguez <mcgrof@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath5k/base.h b/drivers/net/wireless/ath5k/base.h
index d7e03e6..7ec2f37 100644
--- a/drivers/net/wireless/ath5k/base.h
+++ b/drivers/net/wireless/ath5k/base.h
@@ -172,6 +172,7 @@
 	struct tasklet_struct	txtq;		/* tx intr tasklet */
 	struct ath5k_led	tx_led;		/* tx led */
 
+	spinlock_t		block;		/* protects beacon */
 	struct ath5k_buf	*bbuf;		/* beacon buffer */
 	unsigned int		bhalq,		/* SW q for outgoing beacons */
 				bmisscount,	/* missed beacon transmits */