zbd: Fix read with verify

zbd: Fix read with verify

For a read only workload with verify option enabled, executing
zbd_replay_write_order() will ignore target zones that are full and try
to open another zone. This either triggers an assert if max_open_zones
is unused, or result in verify failing. Fix this by executing
zbd_replay_write_order() only for writing workloads. This fix is also
consistent with the fact that zoned devices do not implicitly open
zones for read operations.

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