d2lte: Lower speakerphone volume a touch.

Recent change was causing some feedback/echo on speakerphone calls,
drop it down a few % and see how it goes.

Change-Id: Ie91f92edc1cf1f4d4cd25c41c4ddb044d5d6023b
Merge "d2lte: Lower speakerphone volume a touch." into cm-11.0