GXP support into OpenBMC kernel

[Verdun, Jean-Marie]

Hi Joel,

Thanks for your answer. Here is the process that I propose, let me know if that doesn't match your expectation.

- We keep upstreaming into 6.2x and we will warn you about need to backport (I hope it will be easy but I think it will be the case)
- In parallel, we start enabling some of our gen11 machines into openbmc repo and point to standard openbmc kernel. We have decided to have a fine grain process to upstream and do it one step at a time. That might look like a little bit overkill, but I think that will be efficient. 
- When we identify potential bottleneck, we discuss through the mailing list about them, and get your feedbacks on how to process.

We would like to apply the same approach with u-boot, if that is ok for you ?

JM