mixer_paths: Remove unnecessary mixer controls in mixers_path.xml

- Cleaning unused mixer controls from the mixer path file
CRs-Fixed: 600664

Change-Id: I7e59136e6b2642c3d0e700d13756de9e695febac
mixer_paths: fix mixer commands for BT-SCO-WB for mic and headset

Add mixer commands for missing BT-SCO-WB for mic and headset cases.

CRs-Fixed: 594952
Change-Id: I51c262f3ccc03e4aa8ef5448ca6e06f53eda773c
mixer_paths: Fix mixer commands for FM

FM loopback is default enabled resulting in loopback
port mixer commands active after boot even if no FM running.

Crs-fixed: 626651
Change-Id: I988593fd5377b3496aef132165be5980db340a30
mixer_paths: fix default value for TTY mode

Fix the default value for the TTY mode mixer
control. This will avoid sending invalid mode
to ADSP and is needed to disable the TTY
mode properly.

Change-Id: If9524b4d9a7553fdb3f3d8fac870ad5ef4890dc1
CRs-fixed: 615264
mixer_paths: add echo reference path

Adding the mixer control for echo reference.
This change removes the hardcoding and adds mixer
control in the xml file.
Change-Id: Ia8895e9c2cb57aaa0c0233cc503de7db3bc9d09d
mixer_paths: Initialize Fm volume to zero

 -A glitch is heard during device switch in FM playback.
  Since , FM volume is initialized to 1, this gain is not
  applied when fm usecase is enabled/disabled as the old
  and new value is the same.
 -Initializing FM volume to zero.

Change-Id: I96fc31c271de98ba0b684828b1e5458246177550
CRs-Fixed: 646384
enable audio features

* Lollipop audio HAL wants features explicitly enabled
* There seems to be no need for separate audio policy
  extension anymore(?)

Change-Id: I19014ac32a3aad648956118b67159aafdeb0851c
remove more deprecated qcom hardware flags

* https://github.com/CyanogenMod/android_build/commit/dac2f53a6b2a8a7596f064b6ca595494754988f8
* https://github.com/CyanogenMod/android_build/commit/d4507067047fe6fdd68e941c97f71beb61e8c594

Change-Id: I5a7c92bb6c37f57d1c3ba97d326703564db35987