Added a couple of missing lock guards

src/UpscalerGraphicsDevice.h

@@ -72,6 +72,8 @@ public:
 
     void ClearTextureTable(uint32_t featureSlot) override
     {
+        std::lock_guard<std::mutex> lock(m_Mutex);
+
         if (featureSlot < 0 || featureSlot >= m_Features.size())
             return;
 
@@ -80,6 +82,8 @@ public:
 
     void SetTextureSlot(uint32_t featureSlot, uint32_t textureSlot, UnityTextureID textureID, uint32_t width, uint32_t height) override
     {
+        std::lock_guard<std::mutex> lock(m_Mutex);
+
         if (featureSlot < 0 || featureSlot >= m_Features.size())
             return;