AudioService: clear caller identity before broadcasting intent

As setMicrophoneMute API is processed inside a binder call,
the caller identity mnust be cleared before broadcasting intent
ACTION_MICROPHONE_MUTE_CHANGED.

Bug: 144406103
Test: make
Change-Id: I2a573932ebcd92cd76bf734a4c6c8dfd28d9bbb7
1 file changed