Core/VideoCommon: Clear on HiresTexture::Init

Resolves duplicate OSD messages for Loading and Found custom textures.
VideoBackend initialization results in HiresTexture::Init being called.
We already call HiresTexture::Update when OnNewTitleLoad is called.

Source/Core/VideoCommon/HiresTextures.cpp

@@ -79,7 +79,7 @@ std::pair<std::string, bool> GetNameArbPair(const TextureInfo& texture_info)
 
 void HiresTexture::Init()
 {
-  Update();
+  Clear();
 }
 
 void HiresTexture::Shutdown()