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/am33xx.dtsi b/arch/arm/dts/am33xx.dtsi
index 5871344..a9ce8fd 100644
--- a/arch/arm/dts/am33xx.dtsi
+++ b/arch/arm/dts/am33xx.dtsi
@@ -1,11 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Device Tree Source for AM33XX SoC
  *
- * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
- *
- * This file is licensed under the terms of the GNU General Public License
- * version 2.  This program is licensed "as is" without any warranty of any
- * kind, whether express or implied.
+ * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
  */
 
 #include <dt-bindings/bus/ti-sysc.h>