Qt: Fix postfx option pane not loading

src/util/postprocessing.cpp

@@ -263,6 +263,7 @@ std::vector<PostProcessing::ShaderOption> PostProcessing::Config::GetStageOption
   if (!shader)
     return ret;
 
+  shader->LoadOptions(si, section);
   ret = shader->TakeOptions();
   return ret;
 }

src/util/postprocessing_shader.cpp

@@ -66,7 +66,7 @@ std::vector<PostProcessing::ShaderOption> PostProcessing::Shader::TakeOptions()
   return std::move(m_options);
 }
 
-void PostProcessing::Shader::LoadOptions(SettingsInterface& si, const char* section)
+void PostProcessing::Shader::LoadOptions(const SettingsInterface& si, const char* section)
 {
   for (ShaderOption& option : m_options)
   {

src/util/postprocessing_shader.h

@@ -38,7 +38,7 @@ public:
   virtual bool IsValid() const = 0;
 
   std::vector<ShaderOption> TakeOptions();
-  void LoadOptions(SettingsInterface& si, const char* section);
+  void LoadOptions(const SettingsInterface& si, const char* section);
 
   const ShaderOption* GetOptionByName(const std::string_view& name) const;
   ShaderOption* GetOptionByName(const std::string_view& name);