audiohal: Re-implement stream read and write using FMQ

Result: no hwbinder calls due read / write session.

Added IStream.close method for explicitly freeing up of resources
consumed by the stream before automatic server objects reaping
gets to it.

Test: make, perform Loopback RTT, check traces
Bug: 30222631
Change-Id: I678559f6ef30026685df787cd2ba7c2ee449ed27
diff --git a/audio/2.0/default/Stream.cpp b/audio/2.0/default/Stream.cpp
index f214eed..62b34a3 100644
--- a/audio/2.0/default/Stream.cpp
+++ b/audio/2.0/default/Stream.cpp
@@ -253,6 +253,10 @@
     return Void();
 }
 
+Return<Result> Stream::close()  {
+    return Result::NOT_SUPPORTED;
+}
+
 } // namespace implementation
 }  // namespace V2_0
 }  // namespace audio