nvme: set the PRACT bit when using Write Zeroes with T10 PI

When using Write Zeroes on a namespace that has protection
information enabled they behavior without the PRACT bit
counter-intuitive and will generally lead to validation failures
when reading the written blocks.  Fix this by always setting the
PRACT bit that generates matching PI data on the fly.

Fixes: 6e02318e

 ("nvme: add support for the Write Zeroes command")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>