pNFS: Modify pnfs_update_layout tracepoints to use layout stateid

Instead of displaying a layout segment pointer in these tracepoints,
let's use the layout stateid, now that Olga gave us a set of tools for
displaying them.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4trace.c

@@ -6,6 +6,7 @@
 #include "internal.h"
 #include "nfs4session.h"
 #include "callback.h"
+#include "pnfs.h"
 
 #define CREATE_TRACE_POINTS
 #include "nfs4trace.h"