drm: unused argument warning messages

Change-Id: Ifd8a470ffa02f986427c5f36380d70494efe864d
diff --git a/drm/libdrmframework/DrmManagerClientImpl.cpp b/drm/libdrmframework/DrmManagerClientImpl.cpp
index 9457bb6..6afb23b 100644
--- a/drm/libdrmframework/DrmManagerClientImpl.cpp
+++ b/drm/libdrmframework/DrmManagerClientImpl.cpp
@@ -350,7 +350,7 @@
     }
 }
 
-void DrmManagerClientImpl::DeathNotifier::binderDied(const wp<IBinder>& who) {
+void DrmManagerClientImpl::DeathNotifier::binderDied(const wp<IBinder>& /*who*/) {
     Mutex::Autolock lock(sMutex);
     DrmManagerClientImpl::sDrmManagerService.clear();
     ALOGW("DrmManager server died!");