ath6kl: Add tx_complete() to struct htc_ep_callbacks

This is needed by the USB code. Also while at it replace one void pointer
with a properly typed pointer.

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath6kl/htc.h b/drivers/net/wireless/ath/ath6kl/htc.h
index 5027ccc..7b0c489 100644
--- a/drivers/net/wireless/ath/ath6kl/htc.h
+++ b/drivers/net/wireless/ath/ath6kl/htc.h
@@ -319,6 +319,7 @@
 };
 
 struct htc_ep_callbacks {
+	void (*tx_complete) (struct htc_target *, struct htc_packet *);
 	void (*rx) (struct htc_target *, struct htc_packet *);
 	void (*rx_refill) (struct htc_target *, enum htc_endpoint_id endpoint);
 	enum htc_send_full_action (*tx_full) (struct htc_target *,