m8: Fix VoIP clients

From xda user @dante020

This fixes no sound coming from the earpiece during a call (tested with Google Voice). This issue can be reproduced on all SIP clients such as CSipSimple, Media5 Fone, Bria, Skype, as well as the built-in CM dialer SIP client.

Change-Id: Ia1f8a11893b14d3a419b8dcd88818084cc1b024a