xhci: trace debug statements related to ring expansion

This patch defines a new trace event, which is called xhci_dbg_ring_expansion
and belongs to the event class xhci_log_msg, and adds tracepoints that trace
the debug messages associated with the expansion of endpoint ring when there
is not enough space allocated to hold all pending TRBs.

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index ef27470..b150360 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -348,7 +348,8 @@
 		return -ENOMEM;
 
 	xhci_link_rings(xhci, ring, first, last, num_segs);
-	xhci_dbg(xhci, "ring expansion succeed, now has %d segments\n",
+	xhci_dbg_trace(xhci, trace_xhci_dbg_ring_expansion,
+			"ring expansion succeed, now has %d segments",
 			ring->num_segs);
 
 	return 0;