nvme-pci: fix DMA direction of unmapping integrity data

DMA direction should be taken in dma_unmap_page() for unmapping integrity
data.

Fix this DMA direction, and reported in Guangwu's test.
Reported-by: Guangwu Zhang <guazhang@redhat.com>
Fixes: 4aedb705 ("nvme-pci: split metadata handling from nvme_map_data / nvme_unmap_data")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/host/pci.c

@@ -967,7 +967,7 @@ static __always_inline void nvme_pci_unmap_rq(struct request *req)
 	        struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 
 		dma_unmap_page(dev->dev, iod->meta_dma,
-			       rq_integrity_vec(req)->bv_len, rq_data_dir(req));
+			       rq_integrity_vec(req)->bv_len, rq_dma_dir(req));
 	}
 
 	if (blk_rq_nr_phys_segments(req))