Add proximity wake flag

Use frameworks opt-in functionality.

Depends on http://review.cyanogenmod.org/#/c/69169/

Change-Id: Ib078b65252bd5ca4da3d71d8d73f66ba7e8bf333
Update mixer paths
ril: Remove redundant check in message interception

This isn't necessary anymore, the request can be fetched directly

Change-Id: Id5d632136476e43f17bbd65c9157ddc318b8ce9b