audiopolicy: add Volume for attribute and callback native APIs

Change-Id: I259de42452d2802aa8dbd553f56040dea6995a93
Signed-off-by: François Gaffie <francois.gaffie@renault.com>

Bug: 124767636
Test: make
diff --git a/services/audiopolicy/tests/AudioPolicyTestClient.h b/services/audiopolicy/tests/AudioPolicyTestClient.h
index 6ae354b..8854eb2 100644
--- a/services/audiopolicy/tests/AudioPolicyTestClient.h
+++ b/services/audiopolicy/tests/AudioPolicyTestClient.h
@@ -73,6 +73,7 @@
                                 int /*delayMs*/) override { return NO_INIT; }
     void onAudioPortListUpdate() override { }
     void onAudioPatchListUpdate() override { }
+    void onAudioVolumeGroupChanged(volume_group_t /*group*/, int /*flags*/) override { }
     audio_unique_id_t newAudioUniqueId(audio_unique_id_use_t /*use*/) override { return 0; }
     void onDynamicPolicyMixStateUpdate(String8 /*regId*/, int32_t /*state*/) override { }
     void onRecordingConfigurationUpdate(int event __unused,