block: expose write streams for block device nodes

Use the per-kiocb write stream if provided, or map temperature hints to
write streams (which is a bit questionable, but this shows how it is
done).

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
[kbusch: removed statx reporting]
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Link: https://lore.kernel.org/r/20250506121732.8211-6-joshi.k@samsung.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>