time: Remove auto timezone consideration

GetTimeZoneString no longer reports a setting unique to yuzu, so we
can assume a valid timezone string in core.

src/core/hle/service/time/time_manager.cpp

@@ -119,14 +119,6 @@ struct TimeManager::Impl final {
         time_zone_content_manager.GetTimeZoneManager().MarkAsInitialized();
     }
 
-    static s64 GetExternalTimeZoneOffset() {
-        // With "auto" timezone setting, we use the external system's timezone offset
-        if (Settings::GetTimeZoneString() == "auto") {
-            return Common::TimeZone::GetCurrentOffsetSeconds().count();
-        }
-        return 0;
-    }
-
     void SetupStandardSteadyClock(Core::System& system_, Common::UUID clock_source_id,
                                   Clock::TimeSpanType setup_value,
                                   Clock::TimeSpanType internal_offset, bool is_rtc_reset_detected) {
@@ -297,13 +289,4 @@ void TimeManager::SetupTimeZoneManager(std::string location_name,
     impl->SetupTimeZoneManager(location_name, time_zone_updated_time_point,
                                total_location_name_count, time_zone_rule_version, vfs_file);
 }
-
-/*static*/ s64 TimeManager::GetExternalTimeZoneOffset() {
-    // With "auto" timezone setting, we use the external system's timezone offset
-    if (Settings::GetTimeZoneString() == "auto") {
-        return Common::TimeZone::GetCurrentOffsetSeconds().count();
-    }
-    return 0;
-}
-
 } // namespace Service::Time

src/core/hle/service/time/time_manager.h

@@ -64,8 +64,6 @@ public:
                               std::size_t total_location_name_count, u128 time_zone_rule_version,
                               FileSys::VirtualFile& vfs_file);
 
-    static s64 GetExternalTimeZoneOffset();
-
 private:
     Core::System& system;
 

src/core/hle/service/time/time_zone_content_manager.cpp

@@ -76,25 +76,14 @@ TimeZoneContentManager::TimeZoneContentManager(Core::System& system_)
     : system{system_}, location_name_cache{BuildLocationNameCache(system)} {}
 
 void TimeZoneContentManager::Initialize(TimeManager& time_manager) {
-    std::string location_name;
     const auto timezone_setting = Settings::GetTimeZoneString();
-    if (timezone_setting == "auto") {
-        const struct std::chrono::tzdb& time_zone_data = std::chrono::get_tzdb();
-        const std::chrono::time_zone* current_zone = time_zone_data.current_zone();
-        std::string_view current_zone_name = current_zone->name();
-        location_name = current_zone_name;
-    } else if (timezone_setting == "default") {
-        location_name = Common::TimeZone::GetDefaultTimeZone();
-    } else {
-        location_name = timezone_setting;
-    }
 
     if (FileSys::VirtualFile vfs_file;
-        GetTimeZoneInfoFile(location_name, vfs_file) == ResultSuccess) {
+        GetTimeZoneInfoFile(timezone_setting, vfs_file) == ResultSuccess) {
         const auto time_point{
             time_manager.GetStandardSteadyClockCore().GetCurrentTimePoint(system)};
-        time_manager.SetupTimeZoneManager(location_name, time_point, location_name_cache.size(), {},
-                                          vfs_file);
+        time_manager.SetupTimeZoneManager(timezone_setting, time_point, location_name_cache.size(),
+                                          {}, vfs_file);
     } else {
         time_zone_manager.MarkAsInitialized();
     }