rt2x00: Minor optimizazion in txdone path

We can save an indirect function call + some instructions for fetching
the actual function pointer by passing the driver specific txwi pointer
directly from rt2800pci/rt2800usb to rt2800lib instead of using the
rt2800_drv_get_txwi callback.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
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/rt2800usb.c b/drivers/net/wireless/rt2x00/rt2800usb.c
index 5075593..7917614 100644
--- a/drivers/net/wireless/rt2x00/rt2800usb.c
+++ b/drivers/net/wireless/rt2x00/rt2800usb.c
@@ -534,7 +534,8 @@
 		if (!entry || rt2x00queue_empty(queue))
 			break;
 
-		rt2800_txdone_entry(entry, reg);
+		rt2800_txdone_entry(entry, reg,
+				    rt2800usb_get_txwi(entry));
 	}
 }