VideoCommon: Add reasons for disabled VS expand

Source/Core/VideoCommon/VideoBackendBase.cpp

@@ -274,6 +274,7 @@ void VideoBackendBase::PopulateBackendInfo()
   // a value from the previously used renderer
   g_Config.backend_info = {};
   ActivateBackend(Config::Get(Config::MAIN_GFX_BACKEND));
+  g_Config.backend_info.DisplayName = g_video_backend->GetDisplayName();
   g_video_backend->InitBackendInfo();
   // We validate the config after initializing the backend info, as system-specific settings
   // such as anti-aliasing, or the selected adapter may be invalid, and should be checked.

Source/Core/VideoCommon/VideoConfig.h

@@ -174,6 +174,7 @@ struct VideoConfig final
   struct
   {
     APIType api_type = APIType::Nothing;
+    std::string DisplayName;
 
     std::vector<std::string> Adapters;  // for D3D
     std::vector<u32> AAModes;