Reduce number of copies into unmapExternalTextureBuffer

Make unmapExternalTextureBuffer take in an rvalue of sp<GraphicBuffer>,
which reduces the number sp copies.

Bug: 215661436
Test: builds
Change-Id: I4f9b6e3d6863ce6815810fdda038dc9e730f0b44
diff --git a/libs/renderengine/threaded/RenderEngineThreaded.h b/libs/renderengine/threaded/RenderEngineThreaded.h
index 168e2d2..6eb108e 100644
--- a/libs/renderengine/threaded/RenderEngineThreaded.h
+++ b/libs/renderengine/threaded/RenderEngineThreaded.h
@@ -69,7 +69,7 @@
 
 protected:
     void mapExternalTextureBuffer(const sp<GraphicBuffer>& buffer, bool isRenderable) override;
-    void unmapExternalTextureBuffer(const sp<GraphicBuffer>& buffer) override;
+    void unmapExternalTextureBuffer(sp<GraphicBuffer>&& buffer) override;
     bool canSkipPostRenderCleanup() const override;
     void drawLayersInternal(const std::shared_ptr<std::promise<FenceResult>>&& resultPromise,
                             const DisplaySettings& display,