IB/mlx5: Avoid unnecessary typecast

IB device pointer is already available while deallocating IB device,
Hence do not typecast it.

Link: https://lore.kernel.org/r/20190723065733.4899-9-leon@kernel.org
Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -6933,7 +6933,7 @@ static void *mlx5_ib_add(struct mlx5_core_dev *mdev)
 	dev->port = kcalloc(num_ports, sizeof(*dev->port),
 			     GFP_KERNEL);
 	if (!dev->port) {
-		ib_dealloc_device((struct ib_device *)dev);
+		ib_dealloc_device(&dev->ib_dev);
 		return NULL;
 	}