IAudioFlingerClient::ioConfigChanged param2 const

The 3rd parameter (param2) to AudioFlingerClient::ioConfigChanged
is used as an input.  So changed it from void * to const void *.
It is then cast to const OutputDescriptor *
or const audio_stream_type_t * depending on the event.

Change-Id: Ieec0d284f139b74b3389b5ef69c7935a8e5650ee