timers: Add rb_init_node() to allow for stack allocated rb nodes

In cases where a timerqueue_node or some structure that utilizes
a timerqueue_node is allocated on the stack, gcc would give warnings
caused by the timerqueue_init()'s calling RB_CLEAR_NODE, which
self-references the nodes uninitialized data.

The solution is to create an rb_init_node() function that zeros
the rb_node structure out and then calls RB_CLEAR_NODE(), and
then call the new init function from timerqueue_init().

CC: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/include/linux/timerqueue.h b/include/linux/timerqueue.h
index a520fd7..5088727 100644
--- a/include/linux/timerqueue.h
+++ b/include/linux/timerqueue.h
@@ -39,7 +39,7 @@
 
 static inline void timerqueue_init(struct timerqueue_node *node)
 {
-	RB_CLEAR_NODE(&node->node);
+	rb_init_node(&node->node);
 }
 
 static inline void timerqueue_init_head(struct timerqueue_head *head)