Update calls to IInterface::asBinder()

to use the new static version.

Change-Id: I89a5988a0ac694ffc04d88cf939e8455bf925d4c
diff --git a/drm/libdrmframework/DrmManagerClientImpl.cpp b/drm/libdrmframework/DrmManagerClientImpl.cpp
index 2d2c90e..9457bb6 100644
--- a/drm/libdrmframework/DrmManagerClientImpl.cpp
+++ b/drm/libdrmframework/DrmManagerClientImpl.cpp
@@ -346,7 +346,7 @@
 DrmManagerClientImpl::DeathNotifier::~DeathNotifier() {
     Mutex::Autolock lock(sMutex);
     if (NULL != sDrmManagerService.get()) {
-        sDrmManagerService->asBinder()->unlinkToDeath(this);
+        IInterface::asBinder(sDrmManagerService)->unlinkToDeath(this);
     }
 }