Core/VideoCommon: Fix duplicate OSD Custom Textures messages

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.
Thus we can remove HiresTextures::Init completely as it is redundant.

Source/Core/VideoCommon/TextureCacheBase.cpp

@@ -99,8 +99,6 @@ TextureCacheBase::TextureCacheBase()
   TexDecoder_SetTexFmtOverlayOptions(m_backup_config.texfmt_overlay,
                                      m_backup_config.texfmt_overlay_center);
 
-  HiresTexture::Init();
-
   TMEM::InvalidateAll();
 }