Revert "blk-mq: fix null pointer dereference in blk_mq_queue_tag_busy_ite"

【环境信息】
硬件信息：不涉及
软件信息：openEuler-1.0-LTS
【问题描述】
Commit fea9f92f1748 introduce the bug. It is a patch for performance
optimization and this version doesn't have to backport it.
blk_mq_queue_tag_busy_iter() won't access q->tag_set->flags or reference
other fields in q that is uninitialized at present. 64ba823fd427 will
make io hang for special scsi drivers(e.x. ata_piix). Revert it.

【问题复现步骤】
使用scsi驱动如ata_piix起虚拟机
【预期结果】
编译内核后启动虚拟机失败，触发Kernel panic - not syncing: hung_task: blocked tasks
【附件信息】
![输入图片说明](https://foruda.gitee.com/images/1660785125069214748/error截图.png "Error截图.png")
【补丁信息】
```
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index c24802fe6ab2..bee92ab06a5e 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -374,13 +374,6 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
        struct blk_mq_hw_ctx *hctx;
        int i;

-       /*
-        * For dm, it can run here after register_disk, but the queue has not
-        * been initialized yet. Check QUEUE_FLAG_REGISTERED prevent null point
-        * access.
-        */
-       if (!test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
-               return;
        /*
         * __blk_mq_update_nr_hw_queues will update the nr_hw_queues and
         * queue_hw_ctx after freeze the queue, so we use q_usage_counter

```

GVP openEuler/kernel

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GVPopenEuler/kernel

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