m7-common: set mtp only in properties

* adb now appears to be set by default, causing a duplicate to appear.
  This can cause issues with USB mode selection.

Change-Id: I9b4096de49677da2d369d5e2e06db5f86e6ae5de
m7-common: disable LPA temporarily

* Pending proper support in audio HAL

Change-Id: I788172705e973c84b007189a2042a6a8e0fd31ab
m7-common: update wpa_supplicant config

Change-Id: Iaf2aa51327463ee88050c1890f2d5231e41d92a1