audio: Simplify AudioHalBinderServiceUtil::waitForFired()

Return the std::condition::wait_for() return value instead of reading
the variable 'fired' again. See also
https://en.cppreference.com/w/cpp/thread/condition_variable/wait_for.

Change-Id: I48c270f5446f61b2ad828b19a1fc294737a123dd
Signed-off-by: Bart Van Assche <bvanassche@google.com>
diff --git a/audio/aidl/vts/AudioHalBinderServiceUtil.h b/audio/aidl/vts/AudioHalBinderServiceUtil.h
index b4b4632..403690e 100644
--- a/audio/aidl/vts/AudioHalBinderServiceUtil.h
+++ b/audio/aidl/vts/AudioHalBinderServiceUtil.h
@@ -71,8 +71,7 @@
 
         bool waitForFired(std::chrono::milliseconds timeoutMs) {
             std::unique_lock<std::mutex> lock(mutex);
-            condition.wait_for(lock, timeoutMs, [this]() { return fired; });
-            return fired;
+            return condition.wait_for(lock, timeoutMs, [this]() { return fired; });
         }
 
       private: