btrfs: Remove unnecessary ClearPageUptodate for raid56

PageUptodate flag already initialized to 0 for new page,
no need to set it again.
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

fs/btrfs/raid56.c

@@ -1032,7 +1032,6 @@ static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
 		if (!page)
 			return -ENOMEM;
 		rbio->stripe_pages[i] = page;
-		ClearPageUptodate(page);
 	}
 	return 0;
 }
@@ -2273,7 +2272,6 @@ static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
 			if (!page)
 				return -ENOMEM;
 			rbio->stripe_pages[index] = page;
-			ClearPageUptodate(page);
 		}
 	}
 	return 0;