NvHost/Core: Address Feedback.

src/core/core.h

@@ -7,6 +7,7 @@
 #include <cstddef>
 #include <functional>
 #include <memory>
+#include <mutex>
 #include <string>
 #include <vector>
 
@@ -160,7 +161,8 @@ public:
     /// Shutdown the emulated system.
     void Shutdown();
 
-    void stallForGPU(bool pause);
+    std::unique_lock<std::mutex> StallCPU();
+    void UnstallCPU();
 
     /**
      * Load an executable application.