scsi: sd_zbc: Simplify sd_zbc_check_zones()

Now that the block layer generic zone revalidation code in
blk_revalidate_disk_zones() checks for power of 2 zone size, there is no
need to do it in sd_zbc_check_zones(). Remove this check.

Link: https://lore.kernel.org/r/20191220075823.400072-2-damien.lemoal@wdc.com


Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>