Ensure doze sensors can be registered when screen on.

Prior to this, the sensors were always off if the screen was on. This
meant that if a notifciation came in, the phone wouldn't react to
being picked up (the screen would show the notification but otherwise
remain dim). With this change, the phone can now wake up.

Fixes: 159086388
Test: manual
Change-Id: Ifdf21fbadc9381e843f4656aeacdfce4a12d02c8