mm/mempool: fix the entry condition for semaphore during mempool allocation

When the mempool uses the waitsem semaphore for memory allocation,
the flowing two conditions must be satisfied simultaneously:
its wait variable is set to true, and the expandsize variable is set to 0

Signed-off-by: zhanxiaoqi <zhanxiaoqi@bytedance.com>

mm/mempool/mempool.c

@@ -394,6 +394,7 @@ retry:
               blk = mempool_remove_queue(pool, &pool->queue);
             }
           else if (!pool->wait ||
+                   pool->expandsize > 0 ||
                    nxsem_wait_uninterruptible(&pool->waitsem) < 0)
             {
               return NULL;