More audio use case enhacements

- Use TW's "Call Main Mic" for "Speaker DMIC Endfire".
  - Resolves speakerphone echo by using only the main (bottom) mic.

- Clone "Handset" to "Line", as audio-caf uses "Line" by default now.
  - Also matches TW's "Main Mic".
Revert "d2: Limit MDP composition to 3 layers"

fixed in this commit http://review.cyanogenmod.org/#/c/29744/

This reverts commit c91ae499cf5ace42dcd0044736207d5161a58e07

Change-Id: I7ac5a74af96142125d50f9b241efc2dd9cc5be01