rcutorture: Make scenario TREE07 build CONFIG_PREEMPT_LAZY=y

This commit tests lazy preemption by causing the TREE07 rcutorture
scenario to build its kernel with CONFIG_PREEMPT_LAZY=y.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>

tools/testing/selftests/rcutorture/configs/rcu/TREE07

@@ -1,7 +1,8 @@
 CONFIG_SMP=y
 CONFIG_NR_CPUS=16
-CONFIG_PREEMPT_NONE=y
+CONFIG_PREEMPT_NONE=n
 CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT_LAZY=y
 CONFIG_PREEMPT=n
 CONFIG_PREEMPT_DYNAMIC=n
 #CHECK#CONFIG_TREE_RCU=y