DreamManager: be aware of device lid

If the device lid controls whether the screen goes to sleep, the
DreamManager (and so also DozeMode) should be aware and not try to
activate itself if the cover is closed.

Change-Id: Ie855a8a403548bcabbf1e0824e5cb128110066c2
Signed-off-by: Roman Birg <roman@cyngn.com>