mediatek: fix SPDX license identifier on local DTS files

The SPDX license identifier must be in the first line of a file,
unless there is a shebang (then it's the second line).

Fix this for the local files, do not care about the upstream patches.

While at it, update the identifiers where necessary.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

target/linux/mediatek/dts/mt7622-bananapi-bpi-r64-rootdisk.dts

@@ -1,8 +1,7 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR MIT)
 /*
  * Copyright (c) 2018 MediaTek Inc.
  * Author: Ryder Lee <ryder.lee@mediatek.com>
- *
- * SPDX-License-Identifier: (GPL-2.0-only OR MIT)
  */
 
 /dts-v1/;

target/linux/mediatek/dts/mt7622-elecom-wrc-2533gent.dts

@@ -1,9 +1,8 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR MIT)
 /*
  * Copyright (c) 2017 MediaTek Inc.
  * Author: Ming Huang <ming.huang@mediatek.com>
  *	   Sean Wang <sean.wang@mediatek.com>
- *
- * SPDX-License-Identifier: (GPL-2.0-only OR MIT)
  */
 
 /dts-v1/;

target/linux/mediatek/dts/mt7623a-unielec-u7623-02-emmc-512m.dts

@@ -1,7 +1,6 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR MIT)
 /*
  * Copyright 2018 Kristian Evensen <kristian.evensen@gmail.com>
- *
- * SPDX-License-Identifier: (GPL-2.0+ OR MIT)
  */
 
 /dts-v1/;

target/linux/mediatek/dts/mt7623a-unielec-u7623-02-emmc.dtsi

@@ -1,7 +1,6 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR MIT)
 /*
  * Copyright 2018 Kristian Evensen <kristian.evensen@gmail.com>
- *
- * SPDX-License-Identifier: (GPL-2.0+ OR MIT)
  */
 
 #include <dt-bindings/input/input.h>