m8: fixup whatsapp audio

add voip_tx as we are missing this which causes problems. .
props to @jackmu95 for discovering this issue.

Change-Id: I8c03de043d5045a96dd12f1a77ee764348b9d24e
m8: Increase the volume step at which the safe volume warning shows

Currently the warning shows up at less than half volume, at normal
listening volume. This bumps it up a bit.

Change-Id: Ie85bb036f75a55b2eb6d1802baba11e632c19908