dm zoned: assign max_io_len correctly

stable inclusion
from linux-4.19.132
commit de07529a9aad73bae29563097372aeda1a3f31c6

--------------------------------

commit 7b237748 upstream.

The unit of max_io_len is sector instead of byte (spotted through
code review), so fix it.

Fixes: 3b1a94c8 ("dm zoned: drive-managed zoned block device target")
Cc: stable@vger.kernel.org
Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>