disk_name for partition 0 just copies out the disk_name field.  Replace
the call to disk_name with a %s format specifier.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20210727062518.122108-6-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>