IB/mlx4: Fix race condition between catas error reset and aliasguid flows

Code review revealed a race condition which could allow the catas error
flow to interrupt the alias guid query post mechanism at random points.
Thiis is fixed by doing cancel_delayed_work_sync() instead of
cancel_delayed_work() during the alias guid mechanism destroy flow.

Fixes: a0c64a17 ("mlx4: Add alias_guid mechanism")
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx4/alias_GUID.c

@@ -804,8 +804,8 @@ void mlx4_ib_destroy_alias_guid_service(struct mlx4_ib_dev *dev)
 	unsigned long flags;
 
 	for (i = 0 ; i < dev->num_ports; i++) {
-		cancel_delayed_work(&dev->sriov.alias_guid.ports_guid[i].alias_guid_work);
 		det = &sriov->alias_guid.ports_guid[i];
+		cancel_delayed_work_sync(&det->alias_guid_work);
 		spin_lock_irqsave(&sriov->alias_guid.ag_work_lock, flags);
 		while (!list_empty(&det->cb_list)) {
 			cb_ctx = list_entry(det->cb_list.next,