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/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
index 910870b..b63b9bb 100644
--- a/Documentation/RCU/trace.txt
+++ b/Documentation/RCU/trace.txt
@@ -8,7 +8,7 @@
 for rcutree and next for rcutiny.
 
 
-CONFIG_TREE_RCU and CONFIG_TREE_PREEMPT_RCU debugfs Files and Formats
+CONFIG_TREE_RCU and CONFIG_PREEMPT_RCU debugfs Files and Formats
 
 These implementations of RCU provide several debugfs directories under the
 top-level directory "rcu":
@@ -18,7 +18,7 @@
 rcu/rcu_sched
 
 Each directory contains files for the corresponding flavor of RCU.
-Note that rcu/rcu_preempt is only present for CONFIG_TREE_PREEMPT_RCU.
+Note that rcu/rcu_preempt is only present for CONFIG_PREEMPT_RCU.
 For CONFIG_TREE_RCU, the RCU flavor maps onto the RCU-sched flavor,
 so that activity for both appears in rcu/rcu_sched.