[U-Boot] Mainlining android fastboot support to upstream u-boot

[Zach Pfeffer]

>> What else?  I know one issue maybe why does this need to exist when
>> other solutions exist.  I think that since Android uses it, it is
>> somewhat of a de facto standard.
>
> Oh. Android uses it. It must be The Right Thing (TM), then, I guess.
> Probably like some of the Linux kernel code they use.
>
> This is the killer argument I really like. Thank you very much.

So, "Google uses it aside", it seems that being able to boot via USB
is a useful thing and fastboot is a particular solution; I'm not
entirely sure what other USB u-boot extensions exist apart from those
already mentioned. I find u-boot great and think being able to use USB
instead of a serial port would help adoption. Perhaps we can do away
with fastboot if u-boot had USB support?

> I don't exactly feel motivated to accept just any stuff just because
> company A or project B uses it (even if they appear to be really
> big), or because already lots of efforts have been spent to implement
> something.  On contrary.  Usually an argumentation like that means
> that the design or the implementation are poor. Often both are.
>
> It's 14 years or so that ESR formulated the RERO principle of
> software development; one could really think this is time enough to
> sink in.  Alas, I know I'm an optimist...

Of course part of RERO is "listen to your customers." With the end of
native serial port inclusion on most systems and the proliferation of
USB, it seems that something could be done to the benefit of all.
Actually, it would be kind of cool to have some low level USB config
in u-boot.