m7-common: enable telephony latency optimization

Change-Id: I31a6ff2935517a4f60d43e04cf9de62ecbfc76f9
m7-common: clean up overlay

* No real changes, just re-orders overlay items according to their
  ordering in frameworks/base.
* Satisfies my OCD.

Change-Id: Ie83ec98402bfe03e0ae3e2ad87fb65b20f41d581