fix integration issue with 6eae1c4

Incorporate changes done for e5c7565i ("drm_hwcomposer: refactor Worker")

Change-Id: If2f14bdafb4d7e0c44e3afed978fb64a654e7ac0
diff --git a/vsyncworker.cpp b/vsyncworker.cpp
index 6caf56f..2177521 100644
--- a/vsyncworker.cpp
+++ b/vsyncworker.cpp
@@ -48,21 +48,10 @@
   return InitWorker();
 }
 
-int VSyncWorker::RegisterCallback(std::shared_ptr<VsyncCallback> callback) {
-  int ret = Lock();
-  if (ret) {
-    ALOGE("Failed to lock vsync worker lock %d\n", ret);
-    return ret;
-  }
-
+void VSyncWorker::RegisterCallback(std::shared_ptr<VsyncCallback> callback) {
+  Lock();
   callback_ = callback;
-
-  ret = Unlock();
-  if (ret) {
-    ALOGE("Failed to unlock vsync worker lock %d\n", ret);
-    return ret;
-  }
-  return 0;
+  Unlock();
 }
 
 void VSyncWorker::VSyncControl(bool enabled) {
@@ -138,10 +127,7 @@
   int display = display_;
   std::shared_ptr<VsyncCallback> callback(callback_);
 
-  ret = Unlock();
-  if (ret) {
-    ALOGE("Failed to unlock worker %d", ret);
-  }
+  Unlock();
 
   if (!enabled)
     return;