Host: Remove unused LoadSettings() callback

Was empty and unnecessary.

src/core/system.cpp

@@ -1319,7 +1319,6 @@ void System::LoadSettings(bool display_osd_messages)
   g_settings.ApplySettingRestrictions();
 
   Settings::UpdateLogConfig(si);
-  Host::LoadSettings(si, lock);
   InputManager::ReloadSourcesAndBindings(GetInputSourceSettingsLayer(lock), controller_si, GetHotkeySettingsLayer(lock),
                                          lock);
 

src/core/system_private.h

@@ -90,9 +90,6 @@ void IdlePollUpdate();
 
 namespace Host {
 
-/// Called with the settings lock held, when system settings are being loaded (should load input sources, etc).
-void LoadSettings(const SettingsInterface& si, std::unique_lock<std::mutex>& lock);
-
 /// Called after settings are updated.
 void OnSettingsReloaded();
 

src/duckstation-qt/qthost.cpp

@@ -861,10 +861,6 @@ bool QtHost::LoadResources(Error* error)
   return true;
 }
 
-void Host::LoadSettings(const SettingsInterface& si, std::unique_lock<std::mutex>& lock)
-{
-}
-
 void Host::OnSettingsReloaded()
 {
   emit g_core_thread->settingsReloaded();

src/duckstation-regtest/regtest_host.cpp

@@ -201,10 +201,6 @@ SmallString Host::TranslatePluralToSmallString(const char* context, const char*
   return ret;
 }
 
-void Host::LoadSettings(const SettingsInterface& si, std::unique_lock<std::mutex>& lock)
-{
-}
-
 void Host::OnSettingsReloaded()
 {
 }