Restore original Citra copyright dates in SPDX headers

Update SPDX copyright headers to restore original 2014 Citra Emulator Project
attribution, replacing incorrect 2025 Citron references in:
- bootmanager.cpp
- configure_touch_from_button.cpp
- game_list.cpp
- main.cpp

src/citron/bootmanager.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2025 Citron Homebrew Emulator Project
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <algorithm>

src/citron/configuration/configure_touch_from_button.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2025 Citron Homebrew Emulator Project
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <QInputDialog>

src/citron/game_list.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2025 Citron Homebrew Emulator Project
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <regex>

src/citron/main.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2025 Citron Homebrew Emulator Project
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <cinttypes>