mac80211: free up 2 bytes in skb->cb

Free up 2 bytes in skb->cb to be used for multi-rate retry later.
Move iv_len and icv_len initialization into key alloc.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath5k/base.c b/drivers/net/wireless/ath5k/base.c
index c151588..47be49a 100644
--- a/drivers/net/wireless/ath5k/base.c
+++ b/drivers/net/wireless/ath5k/base.c
@@ -1188,7 +1188,7 @@
 
 	if (info->control.hw_key) {
 		keyidx = info->control.hw_key->hw_key_idx;
-		pktlen += info->control.icv_len;
+		pktlen += info->control.hw_key->icv_len;
 	}
 	ret = ah->ah_setup_tx_desc(ah, ds, pktlen,
 		ieee80211_get_hdrlen_from_skb(skb), AR5K_PKT_TYPE_NORMAL,