Mutex: Release all held mutexes when a thread exits.

src/core/hle/kernel/mutex.h

@@ -24,4 +24,10 @@ ResultCode ReleaseMutex(Handle handle);
  */
 Handle CreateMutex(bool initial_locked, const std::string& name="Unknown");
 
+/**
+ * Releases all the mutexes held by the specified thread
+ * @param thread Thread that is holding the mutexes
+ */
+void ReleaseThreadMutexes(Handle thread);
+
 } // namespace