zbd: remove zbd_zoned_model ZBD_IGNORE

zbd: remove zbd_zoned_model ZBD_IGNORE

For a job with zonemode=zbd, we do not want any file to be ignored.
Each file's file type in that job should be supported by either zbd.c
or the ioengine. If not, we should return an error.
This way, ZBD_IGNORE becomes redundant and can be removed.

By removing ZBD_IGNORE, we know that all files belonging to a job that
has zonemode=zbd set, will either be a zoned block device, or emulate
a zoned block device.

This means that for jobs that have zonemode=zbd, f->zbd_info will always
be non-NULL. This will make the zbd code slightly easier to reason about
and to maintain.

When removing zbd_zoned_model ZBD_IGNORE, define the new first enum value
as 0x1, so that we avoid potential ABI problems with existing binaries.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>