drbd: init queue_limits->max_hw_wzeroes_unmap_sectors parameter

The parameter max_hw_wzeroes_unmap_sectors in queue_limits should be
equal to max_write_zeroes_sectors if it is set to a non-zero value.
However, when the backend bdev is specified, this parameter is
initialized to UINT_MAX during the call to blk_set_stacking_limits(),
while only max_write_zeroes_sectors is adjusted. Therefore, this
discrepancy triggers a value check failure in blk_validate_limits().

Since the drvd driver doesn't yet support unmap write zeroes, so fix
this failure by explicitly setting max_hw_wzeroes_unmap_sectors to
zero.

Fixes: 0c40d7cb ("block: introduce max_{hw|user}_wzeroes_unmap_sectors to queue limits")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>