sched: fair: Disable double lock/unlock balance in detach_task()

CONFIG_LOCK_STAT shows warnings in detach_task() for releasing a
pinned lock. The warnings are due to the calls to
double_unlock_balance() added to snapshot WALT. Lets disable them if
not building with SCHED_WALT.

Bug: 123720375
Change-Id: Ibfa28b1434fa6006fa0117fd2df1a3eadb321568
Signed-off-by: Miguel de Dios <migueldedios@google.com>
Signed-off-by: Alexander Winkowski <dereference23@outlook.com>

kernel/sched/fair.c

@@ -9307,11 +9307,15 @@ static void detach_task(struct task_struct *p, struct lb_env *env)
 	p->on_rq = TASK_ON_RQ_MIGRATING;
 	deactivate_task(env->src_rq, p, DEQUEUE_NOCLOCK);
 	lockdep_off();
+#ifdef CONFIG_SCHED_WALT
 	double_lock_balance(env->src_rq, env->dst_rq);
 	if (!(env->src_rq->clock_update_flags & RQCF_UPDATED))
 		update_rq_clock(env->src_rq);
 	set_task_cpu(p, env->dst_cpu);
 	double_unlock_balance(env->src_rq, env->dst_rq);
+#else
+	set_task_cpu(p, env->dst_cpu);
+#endif
 	lockdep_on();
 }