FileSys: rename SaveDataCheck archive to NCCH archive

According to the observation from game and 3dbrew "Used for accessing general NCCH data"

src/core/file_sys/archive_ncch.h

@@ -0,0 +1,34 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <string>
+#include "core/file_sys/archive_backend.h"
+#include "core/hle/result.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// FileSys namespace
+
+namespace FileSys {
+
+/// File system interface to the NCCH archive
+class ArchiveFactory_NCCH final : public ArchiveFactory {
+public:
+    ArchiveFactory_NCCH(const std::string& mount_point);
+
+    std::string GetName() const override {
+        return "NCCH";
+    }
+
+    ResultVal<std::unique_ptr<ArchiveBackend>> Open(const Path& path) override;
+    ResultCode Format(const Path& path, const FileSys::ArchiveFormatInfo& format_info) override;
+    ResultVal<ArchiveFormatInfo> GetFormatInfo(const Path& path) const override;
+
+private:
+    std::string mount_point;
+};
+
+} // namespace FileSys