Deriving the meaning of the nr_zones, rev_nr_zones, zone_blocks and
rev_zone_blocks member variables requires careful analysis of the source
code. Make the meaning of these member variables easier to understand by
introducing struct zoned_disk_info.

Link: https://lore.kernel.org/r/20220421183023.3462291-5-bvanassche@acm.orgReviewed-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Acked-by: NDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>