[U-Boot] [RFC] Migrate to Linux Kernel style SPDX Tags for v2018.05

[Fabio Estevam]

On Sun, May 6, 2018 at 10:45 PM, Tom Rini <trini at konsulko.com> wrote:

> The only place they'll now be allowed, just like with the Linux Kernel,
> is for the first line SDPX tag in some file formats.  Bringing us in
> line with how the kernel goes is overall a good thing I believe.

Correct: it is less confusing to have U-Boot and kernel using the same
SPDX style.