[PATCH] rt2x00: Add get_tx_data_len callback function

The TX datalen must always be converted to a value rt73 and rt2500usb
understand. Both require to use a different size then skb->len.
First off this is required because the descriptor must be added,
but the second is because the value must be a multiple of either 2 or 4,
and it should not be a multiple of the USB packetmax

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index 27bec6e..a392e2a 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -396,6 +396,8 @@
 	int (*write_tx_data) (struct rt2x00_dev *rt2x00dev,
 			      struct data_ring *ring, struct sk_buff *skb,
 			      struct ieee80211_tx_control *control);
+	int (*get_tx_data_len) (struct rt2x00_dev *rt2x00dev, int maxpacket,
+				struct sk_buff *skb);
 	void (*kick_tx_queue) (struct rt2x00_dev *rt2x00dev,
 			       unsigned int queue);