ath9k: reduce the number of functions that access the tx descriptor

Makes it easier to clean up the ath9k_hw descriptor API

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index c016a7a..4eba957 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -213,6 +213,7 @@
 struct ath_buf_state {
 	u8 bf_type;
 	u8 bfs_paprd;
+	u8 ndelim;
 	u16 seqno;
 	unsigned long bfs_paprd_timestamp;
 };