Remove hotplug from simpleramfs

When commit 8397d relocated some configuration from the network to
the hotplug script, it started flooding the console with boot time
noise as the hotplug script references tools that do not exist in
simpleramfs:

[    3.323000] /sbin/hotplug: 51: /sbin/hotplug: is-windcharger: not found
[    3.323000] /sbin/hotplug: 102: /sbin/hotplug: is-network-box: not found

It turns out that there is no hotplug configuration that is required
in early boot while simpleramfs is running.

See b/34131115

Change-Id: If5c523ce87b7ae80e163eb49f9c63ac603a1c130
1 file changed