bonding: return -ENOMEM instead of BUG in alb_upper_dev_walk

bonding: return -ENOMEM instead of BUG in alb_upper_dev_walk

If failed to allocate "tags" or could not find the final upper device from
start_dev's upper list in bond_verify_device_path(), only the loopback
detection of the current upper device should be affected, and the system is
no need to be panic.
So return -ENOMEM in alb_upper_dev_walk to stop walking, print some warn
information when failed to allocate memory for vlan tags in
bond_verify_device_path.

I also think that the following function calls
netdev_walk_all_upper_dev_rcu
---->>>alb_upper_dev_walk
---------->>>bond_verify_device_path
From this way, "end device" can eventually be obtained from "start device"
in bond_verify_device_path, IS_ERR(tags) could be instead of
IS_ERR_OR_NULL(tags) in alb_upper_dev_walk.

Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Link: https://lore.kernel.org/r/20231118081653.1481260-1-shaozhengchao@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>