nvme: revalidate after verifying identifiers

If the namespace identifiers have changed, skip updating the disk
information, as that will register parameters from a mismatched
namespace.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>