using privateInterface does not seem to pick the right address

We tries to deploy k0s in linode (akamai). The vpc in linode seems to do source/dest check (and operates in layer 3), which means that kube-router does not work. to work around this we added a vlan (layer 2), which give the node a second interface, eth1.

Kubelet ended up using the ip of eth0, so we tried to use the `privateInterface` option in the k0sctl config.

For the controller, it picked up the ip address of eth1 as expected, but the worker nodes did not append `--node-ip` to kubelet, which led to node to node config not working.

Should `privateInterface` set `--node-ip` as an extra arg for kubelet?

setting the `privateAddress` did appear to work.

Start at the privateInterface handling in the k0sctl configuration and compare how controller and worker kubelet arguments are generated. Reproduce the Linode setup with eth0 and eth1, then verify whether the worker receives --node-ip for the selected interface and add coverage for the confirmed behavior.

Written by the indexing model from the issue text.