hal: Support the audio amplifier hook

* Original legacy HAL commit:
  Ib236598a5888b2af19bcfb81e285f644a0e84c0d
* Example: http://review.cyanogenmod.org/38221

Change-Id: Ic944a9f7059c78b79322dae9c787cdd8bb029cff
hal: Fix mismerge

 * Should not have been removed.

Change-Id: Icfd71d7621e99d0a164054b3dceff208f80cd28f
audio: msm8660: add presto audio.

Import audio from presto repo, because the local module don't build.

Change-Id: I58418fd4a5aa39302e24a78cb35be76f7902801c
presto: audio: fix error

Change-Id: I6ecf222eeb42efcba45bb2639f0d97b7706fd188
presto: audio: define PRESTO_AUDIO

Change-Id: Ie801771f7409dfb4215c99656482623c6e419c0e
Revert "presto: audio: define PRESTO_AUDIO"

This reverts commit f16f3eca14407c6f4b3987b6d9b3717df8894f17.

Change-Id: Ic091b85c661cb64ddef887131a8cde1e5a076801