nvme: set pi_offset only when checksum type is not BLK_INTEGRITY_CSUM_NONE

protection information is treated as opaque when checksum type is
BLK_INTEGRITY_CSUM_NONE. In order to maintain the right metadata
semantics, set pi_offset only in cases where checksum type is not
BLK_INTEGRITY_CSUM_NONE.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://lore.kernel.org/20250630090548.3317-4-anuj20.g@samsung.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: Anuj Gupta

drivers/nvme/host/core.c

@@ -1867,9 +1867,10 @@ static bool nvme_init_integrity(struct nvme_ns_head *head,
 	}
 
 	bi->metadata_size = head->ms;
-	if (bi->csum_type)
+	if (bi->csum_type) {
 		bi->pi_tuple_size = head->pi_size;
-	bi->pi_offset = info->pi_offset;
+		bi->pi_offset = info->pi_offset;
+	}
 	return true;
 }