arm: dts: am3x: Update devicetree header comments to sync with v6.3-rc6

Signed-off-by: Andrew Davis <afd@ti.com>
diff --git a/arch/arm/dts/am335x-sl50.dts b/arch/arm/dts/am335x-sl50.dts
index ebb56bd..423f466 100644
--- a/arch/arm/dts/am335x-sl50.dts
+++ b/arch/arm/dts/am335x-sl50.dts
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2015 Toby Churchill - http://www.toby-churchill.com/
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 /dts-v1/;