license: use SPDX identifiers for src/ headers (#3749)

* license: use SPDX identifiers for src/ headers

Replace the full ~20-line MIT license boilerplate on every src/ file with a
two-line SPDX tag (SPDX-FileCopyrightText + SPDX-License-Identifier), following
the REUSE convention used by CircuitPython and the Linux kernel. Removes ~3500
lines of duplicated boilerplate.

1 files changed, 2 insertions, 21 deletions

diff --git a/src/class/printer/printer_device.c b/src/class/printer/printer_device.c
index 158455fc9..bcb6d1d53 100644
--- a/src/class/printer/printer_device.c
+++ b/src/class/printer/printer_device.c
@@ -1,25 +1,6 @@
 /*
- * The MIT License (MIT)
- *
- * Copyright (c) 2026 Ha Thach (tinyusb.org)
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
+ * SPDX-FileCopyrightText: Copyright (c) 2026 Ha Thach (tinyusb.org)
+ * SPDX-License-Identifier: MIT
  *
  * This file is part of the TinyUSB stack.
  */