Revert "BoardConfig: Disable GCC 4.8"

Fixed by https://android.googlesource.com/platform/art/+/e47637cc7c96e654d2c340e6006c232c8078673b

This reverts commit 9e326b78a982f44dcb2f37319304e8ede0cda225.
hammerhead: Better USB audio support

 * Use new QCOM USB audio path which uses the AFE proxy.
 * This fixes the issues with skips and drops when UI sounds play.

Change-Id: I9941d49b669208959353805f43f51874a415eba3
hammerhead: Always keep 3 buffers ready

 * Reduces overall jank system-wide

Change-Id: I37f6021237c81197063d3fd1fd7e5e07626490c9