plugins/src: fix SPDX license identifiers to match the original license text

Author: merge

plugins/crop.c

@@ -3,20 +3,7 @@
  *
  *  Copyright (C) 2024 Martin Kepplinger-Novaković
  *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation, either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * SPDX-License-Identifier: LGPL-2.1
+ * SPDX-License-Identifier: LGPL-2.0-or-later
  */
 #include <errno.h>
 #include <stdlib.h>

plugins/iir.c

@@ -3,20 +3,7 @@
  *
  *  Copyright (C) 2017 Martin Kepplinger
  *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation, either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * SPDX-License-Identifier: LGPL-2.1
+ * SPDX-License-Identifier: LGPL-2.0-or-later
  *
  *
  * Similar to dejitter, this is a smoothing filter to remove low-level noise.

src/tslib.h

@@ -6,22 +6,7 @@
  *  Copyright (C) 2016 Martin Kepplinger <[email protected]>
  *  Copyright (C) 2001 Russell King.
  *
- *  This library is free software; you can redistribute it and/or
- *  modify it under the terms of the GNU Lesser General Public
- *  License as published by the Free Software Foundation; either
- *  version 2.1 of the License, or (at your option) any later version.
- *
- *  This library is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- *  Lesser General Public License for more details.
- *
- *  You should have received a copy of the GNU Lesser General Public
- *  License along with this library; if not, write to the Free Software
- *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
- *  USA
- *
- * SPDX-License-Identifier: LGPL-2.1
+ * SPDX-License-Identifier: LGPL-2.1-or-later
  *
  *
  * Touch screen library interface definitions.