Fix notification led

... by delaying the start of hfd-service a bit. It needs to use the "binder leds" implementation. When started too early, it doesn't find it and uses a fallback, the "dummy leds" implementation.

Only restarting hfd-service in custom libexec script, does not work, maybe it is still too early. I assume, the reason, why it was working after first boot until now, is that the first boot after flashing always takes a bit longer and then maybe the binder-interface (?) already appeared.

Maybe there is a better way of delaying the start of the service, by waiting until binder did appear. But I don't know how to do this.