scripts: update SPDX license names

SPDX moved from GPL-2.0 to GPL-2.0-only and from GPL-2.0+ to
GPL-2.0-or-later. Reflect that in the SPDX license headers.

Signed-off-by: Paul Spooren <mail@aparcar.org>
[adjust commit title, update remaining files]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

scripts/config/lxdialog/checklist.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0+
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  checklist.c -- implements the checklist box
  *

scripts/config/lxdialog/dialog.h

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: GPL-2.0+ */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  *  dialog.h -- common declarations for all dialog modules
  *

scripts/config/lxdialog/inputbox.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0+
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  inputbox.c -- implements the input box
  *

scripts/config/lxdialog/menubox.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0+
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  menubox.c -- implements the menu box
  *

scripts/config/lxdialog/textbox.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0+
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  textbox.c -- implements the text box
  *

scripts/config/lxdialog/util.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0+
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  util.c
  *

scripts/config/lxdialog/yesno.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0+
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  yesno.c -- implements the yes/no box
  *