kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies

Impact: cleanup

We want to remove rcutree internals from the public rcutree.h file for
upcoming kmemtrace changes - but kernel/rcutree_trace.c depends on them.

Introduce kernel/rcutree.h for internal definitions. (Probably all
the other data types from include/linux/rcutree.h could be
moved here too - except rcu_data.)

Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: paulmck@linux.vnet.ibm.com
LKML-Reference: <1237898630.25315.83.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
index d6db3e83..4ee954f 100644
--- a/kernel/rcutree_trace.c
+++ b/kernel/rcutree_trace.c
@@ -43,6 +43,8 @@
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 
+#include "rcutree.h"
+
 static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
 {
 	if (!rdp->beenonline)