Align LibAudioHal V2 and V4 for factorisation

In order to merge the two version, they must first align as much
as possible.

Test: playback music, assistant
Change-Id: If517cc3f4646a224af3e9b3d42b68a75f1801b39
Signed-off-by: Kevin Rocard <krocard@google.com>
diff --git a/media/libaudiohal/2.0/StreamHalHidl.h b/media/libaudiohal/2.0/StreamHalHidl.h
index ebad8ae..8727620 100644
--- a/media/libaudiohal/2.0/StreamHalHidl.h
+++ b/media/libaudiohal/2.0/StreamHalHidl.h
@@ -41,6 +41,7 @@
 using WriteStatus = ::android::hardware::audio::V2_0::IStreamOut::WriteStatus;
 
 namespace android {
+namespace V2_0 {
 
 class DeviceHalHidl;
 
@@ -243,6 +244,7 @@
     status_t prepareForReading(size_t bufferSize);
 };
 
+} // namespace V2_0
 } // namespace android
 
 #endif // ANDROID_HARDWARE_STREAM_HAL_HIDL_H