sched/fair: fix push_task uninitialized in active_load_balance_cpu_stop

Fixes: a80b8c7 ("sched: Extend active balance to accept 'push_task' argument")
Change-Id: I002bd443c1dbb1d63f195f4b8cb7e9998987a6af
Signed-off-by: Tao Huang <huangtao@rock-chips.com>

Author: rkhuangtao

kernel/sched/fair.c

@@ -9358,7 +9358,7 @@ static int active_load_balance_cpu_stop(void *data)
 	struct rq *target_rq = cpu_rq(target_cpu);
 	struct sched_domain *sd = NULL;
 	struct task_struct *p = NULL;
-	struct task_struct *push_task;
+	struct task_struct *push_task = NULL;
 	int push_task_detached = 0;
 	struct lb_env env = {
 		.sd		= sd,