rcu: Remove redundant TREE_PREEMPT_RCU config option

PREEMPT_RCU and TREE_PREEMPT_RCU serve the same function after
TINY_PREEMPT_RCU has been removed. This patch removes TREE_PREEMPT_RCU
and uses PREEMPT_RCU config option in its place.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5e344bb..706a9f7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1278,9 +1278,9 @@
 	union rcu_special rcu_read_unlock_special;
 	struct list_head rcu_node_entry;
 #endif /* #ifdef CONFIG_PREEMPT_RCU */
-#ifdef CONFIG_TREE_PREEMPT_RCU
+#ifdef CONFIG_PREEMPT_RCU
 	struct rcu_node *rcu_blocked_node;
-#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
+#endif /* #ifdef CONFIG_PREEMPT_RCU */
 #ifdef CONFIG_TASKS_RCU
 	unsigned long rcu_tasks_nvcsw;
 	bool rcu_tasks_holdout;