Combined SB + MPU

[eivindbohler]

I'm apologize if this has been asked before, but would it be theoretically possible to combine the SB and MPU firmwares/functionality? I'm very impressed by how this project is progressing, and I'm considering trying to integrate it into another revision of my x86 SBC, the TinyLlama, possibly ditching the Crystal CS4237B altogether. I guess using two rp2040s each running its own firmware could be doable as well, just wanted to check! :)