Update calls to IInterface::asBinder()

to use the new static version.

Change-Id: Ia7b10eb38ca55b72278bfd33d3bf647f338b4e6a

Conflicts:
	media/libmedia/IAudioFlinger.cpp
	media/libmedia/IMediaPlayer.cpp
	media/libstagefright/CameraSource.cpp
diff --git a/media/libmedia/mediametadataretriever.cpp b/media/libmedia/mediametadataretriever.cpp
index 39a239d..8e8a1ed 100644
--- a/media/libmedia/mediametadataretriever.cpp
+++ b/media/libmedia/mediametadataretriever.cpp
@@ -172,7 +172,7 @@
 {
     Mutex::Autolock lock(sServiceLock);
     if (sService != 0) {
-        sService->asBinder()->unlinkToDeath(this);
+        IInterface::asBinder(sService)->unlinkToDeath(this);
     }
 }