[PATCH] ARM: dts: uniphier: use proper SPDX-License-Identifier style

According to Documentation/process/license-rules.rst, move the SPDX License Identifier to the very top of the file. I used C++ comment style not only for the SPDX line but for the entire block because this seems Linus' preference [1]. I also dropped the parentheses to follow the examples in that

[PATCH] ARM: dts: uniphier: use proper SPDX-License-Identifier style

According to Documentation/process/license-rules.rst, move the SPDX License Identifier to the very top of the file. I used C++ comment style not only for the SPDX line but for the entire block because this seems Linus' preference [1]. I also dropped the parentheses to follow the examples in that