xhci: add trace for debug messages related to changing contexts

This patch defines a new trace event, which is called xhci_dbg_context_change
and belongs in the event class xhci_log_msg, and adds tracepoints for tracing
the debug messages related to context updates performed with Configure Endpoint
and Evaluate Context commands.

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 b881bc1..b1bb59b 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -26,6 +26,7 @@
 #include <linux/dmapool.h>
 
 #include "xhci.h"
+#include "xhci-trace.h"
 
 /*
  * Allocates a generic ring segment from the ring pool, sets the dma address,
@@ -661,7 +662,8 @@
 	 * fls(0) = 0, fls(0x1) = 1, fls(0x10) = 2, fls(0x100) = 3, etc.
 	 */
 	max_primary_streams = fls(stream_info->num_stream_ctxs) - 2;
-	xhci_dbg(xhci, "Setting number of stream ctx array entries to %u\n",
+	xhci_dbg_trace(xhci,  trace_xhci_dbg_context_change,
+			"Setting number of stream ctx array entries to %u",
 			1 << (max_primary_streams + 1));
 	ep_ctx->ep_info &= cpu_to_le32(~EP_MAXPSTREAMS_MASK);
 	ep_ctx->ep_info |= cpu_to_le32(EP_MAXPSTREAMS(max_primary_streams)