ath9k_htc: rare leak in ath9k_hif_usb_alloc_tx_urbs()

This is obviously a small picky thing.  The original error handling code
doesn't free the most recent allocations which haven't been added to the
hif_dev->tx.tx_buf list yet.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/hif_usb.c

@@ -609,6 +609,10 @@ static int ath9k_hif_usb_alloc_tx_urbs(struct hif_device_usb *hif_dev)
 
 	return 0;
 err:
+	if (tx_buf) {
+		kfree(tx_buf->buf);
+		kfree(tx_buf);
+	}
 	ath9k_hif_usb_dealloc_tx_urbs(hif_dev);
 	return -ENOMEM;
 }