Add for System Audio Mode

Note that this is skeleton change and do not merge
till get full review from outside of CEC team.

This change introduce four apis for System Audio Mode

1. boolean canChangeSystemAudioMode()
  -  Whether to change system audio mode or not.

2. setSystemAudioMode(boolean enabled, IHdmiControlCallback callback);
  - Change system audio mode.

3. add/removeSystemAudioModeChangeLister.
  - Register/deregister listner for AudioModeChange.

4. getSystemAudioMode()
  - Whether to system audio is enabled or not.

Change-Id: I1e82365155a9f7f6c3ac5d9db4871cf6bad46865
diff --git a/Android.mk b/Android.mk
index 8f7779e..936b41a 100644
--- a/Android.mk
+++ b/Android.mk
@@ -152,6 +152,7 @@
 	core/java/android/hardware/hdmi/IHdmiControlService.aidl \
 	core/java/android/hardware/hdmi/IHdmiDeviceEventListener.aidl \
 	core/java/android/hardware/hdmi/IHdmiHotplugEventListener.aidl \
+	core/java/android/hardware/hdmi/IHdmiSystemAudioModeChangeListener.aidl \
 	core/java/android/hardware/input/IInputManager.aidl \
 	core/java/android/hardware/input/IInputDevicesChangedListener.aidl \
 	core/java/android/hardware/location/IFusedLocationHardware.aidl \