scsi: scsi_debug: Add zone_size_mb module parameter

scsi: scsi_debug: Add zone_size_mb module parameter

Add the zone_size_mb module parameters to control the zone size of a ZBC
device. If the zone size specified is not a divisor of the device capacity,
the last zone of the device will be created as a smaller "runt" zone. This
parameter is ignored for device types other than 0x14 (zbc=2 case).

Note: for testing purposes, zone sizes that are not a power of 2 are
accepted but will result in the drive being rejected by the sd driver.

Link: https://lore.kernel.org/r/20200422104221.378203-7-damien.lemoal@wdc.com
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>