Allow systemd-networkd-wait-online to succeed with one interface

It is enough if one network interface is online, there is no need to wait for all of them.
Without this, when connecting with Wi-Fi and leaving Ethernet disconnected, the network-online.target will get unnecessarily delayed.

configs/releng/airootfs/etc/systemd/system/systemd-networkd-wait-online.service.d/wait-for-only-one-interface.conf

+[Service]
+ExecStart=
+ExecStart=/usr/lib/systemd/systemd-networkd-wait-online --any