Update the viewport when the scissor offset is changed

Fixes a bug with Another Code: R that was noticed when gx-optimization was
merged.

Source/Core/VideoCommon/Src/VertexShaderManager.h

@@ -33,6 +33,8 @@ struct ProjectionHack
 
 void UpdateProjectionHack(int iParams[], std::string sParams[]);
 
+void UpdateViewportWithCorrection();
+
 // The non-API dependent parts.
 class VertexShaderManager
 {