dm-zoned: don't set the discard_alignment queue limit

The discard_alignment queue limit is named a bit misleading means the
offset into the block device at which the discard granularity starts.
Setting it to the discard granularity as done by dm-zoned is mostly
harmless but also useless.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220418045314.360785-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/dm-zoned-target.c

@@ -1001,7 +1001,7 @@ static void dmz_io_hints(struct dm_target *ti, struct queue_limits *limits)
 	blk_limits_io_min(limits, DMZ_BLOCK_SIZE);
 	blk_limits_io_opt(limits, DMZ_BLOCK_SIZE);
 
-	limits->discard_alignment = DMZ_BLOCK_SIZE;
+	limits->discard_alignment = 0;
 	limits->discard_granularity = DMZ_BLOCK_SIZE;
 	limits->max_discard_sectors = chunk_sectors;
 	limits->max_hw_discard_sectors = chunk_sectors;