Revert "md-raid: destroy the bitmap after destroying the thread"

This reverts commit e151db8. Because it
obviously breaks clustered raid as noticed by Neil though it fixed KASAN
issue for dm-raid, let's revert it and fix KASAN issue in next commit.

[1]. https://lore.kernel.org/linux-raid/a6657e08-b6a7-358b-2d2a-0ac37d49d23a@linux.dev/T/#m95ac225cab7409f66c295772483d091084a6d470

Fixes: e151db8 ("md-raid: destroy the bitmap after destroying the thread")
Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: Song Liu <song@kernel.org>

drivers/md/md.c

@@ -6239,11 +6239,11 @@ static void mddev_detach(struct mddev *mddev)
 static void __md_stop(struct mddev *mddev)
 {
 	struct md_personality *pers = mddev->pers;
+	md_bitmap_destroy(mddev);
 	mddev_detach(mddev);
 	/* Ensure ->event_work is done */
 	if (mddev->event_work.func)
 		flush_workqueue(md_misc_wq);
-	md_bitmap_destroy(mddev);
 	spin_lock(&mddev->lock);
 	mddev->pers = NULL;
 	spin_unlock(&mddev->lock);