xhci: Rename variables related to transfer descritpors

urb_priv structure has a count on how many TDs the
URB contains, and how many of those TD's we have handled.

rename:
length -> num_tds
td_cnt -> num_tds_done

No functional changes

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 9193a42..dab2719 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1608,8 +1608,8 @@ struct xhci_scratchpad {
 };
 
 struct urb_priv {
-	int	length;
-	int	td_cnt;
+	int	num_tds;
+	int	num_tds_done;
 	struct	xhci_td	*td[0];
 };