xHCI: store ring's last segment and segment numbers

Store the ring's last segment pointer and number of segments for ring
expansion usage.

Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Tested-by: Paul Zimmerman <Paul.Zimmerman@synopsys.com>
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index eb369a1..2337a8e 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1262,6 +1262,7 @@
 
 struct xhci_ring {
 	struct xhci_segment	*first_seg;
+	struct xhci_segment	*last_seg;
 	union  xhci_trb		*enqueue;
 	struct xhci_segment	*enq_seg;
 	unsigned int		enq_updates;
@@ -1276,6 +1277,7 @@
 	 */
 	u32			cycle_state;
 	unsigned int		stream_id;
+	unsigned int		num_segs;
 	enum xhci_ring_type	type;
 	bool			last_td_was_short;
 };