st-hal: Port the last 2 changes from prop branch

1) sthal: Update LPI logging and other minor changes
Change-Id: I43df1b646f4c284db7d48487cf185a488a2e3181

2) sthal: assign session buffer to NULL after deinit
Change-Id: Ie78784ed251082d587e7f638c5697f03af85c0e3

Change-Id: I6adb404deb37a117be1853a75a5654359c7ac127
5 files changed