nvme: set pi_offset only when checksum type is not BLK_INTEGRITY_CSUM_NONE

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>