Workaround for WiFi timing out at boot although board has no WiFi

[tobozo]

Hi, thanks for maintaining that awesome project!

I have a rpi2b plugged to the lan, this board doesn't have a wifi chip.

Problem: boot time was over 5mn because "sys-subsystem-net-devices-wlan0.device" waited for a timeout before enabling the ethernet connection.

The boot logic seems to assume there's WiFi in every situation, is there any particular reason why WiFi features are enabled even on rpi boards without WiFi chip?

[   10.296005] systemd[1]: Expecting device sys-subsystem-net-devices-wlan0.device - /sys/subsystem/net/devices/wlan0...

$ systemctl status sys-subsystem-net-devices-wlan0.device
○ sys-subsystem-net-devices-wlan0.device - /sys/subsystem/net/devices/wlan0
     Loaded: loaded
     Active: inactive (dead)

Dec 06 12:59:45 octoprint systemd[1]: sys-subsystem-net-devices-wlan0.device: Job sys-subsystem-net-devices-wlan0.device/start timed out.
Dec 06 12:59:45 octoprint systemd[1]: Timed out waiting for device sys-subsystem-net-devices-wlan0.device - /sys/subsystem/net/devices/wlan0.
Dec 06 12:59:45 octoprint systemd[1]: sys-subsystem-net-devices-wlan0.device: Job sys-subsystem-net-devices-wlan0.device/start failed with result 'timeout'.

The wifi timeout at boot went away after I ran the following commands from the shell:

systemctl disable now sys-subsystem-net-devices-wlan0.device
systemctl disable now wifi_powersave@off.service
systemctl disable now copy-network-manager-config@wlan0.service