Add initial support for BeagleBoard PocketBeagle2

[Grippy98]

Hey All,

Let's try this again. Apologies for the last force push, I cleaned it up now so it's a CSC file only.

This PR adds support for the BeagleBoard PocketBeagle 2.
Features, schematics, and purchase links can be found on the board page[0].

Notable features:

• 2x 64-bit Arm-Cortex A53 microprocessor
• 512MB RAM
• On-board ADC via a TI MSPM0L1105 Cortex-M0+ MCU
• Onboard LiPo Battery charger
• JST-SH 1.00mm UART debug port compatible with Pi Debug probe
• Pre-soldered headers compatible with original PocketBeagle

Thanks! and especially many thanks to @glneo for his patience.

[0] https://www.beagleboard.org/boards/pocketbeagle-2

How Has This Been Tested?

Build/Boot tested Bookworm CLI/Minimal on Edge(v6.12) kernel
Build/Boot tested Noble CLI/Minimal on Edge(v6.12) kernel
UART works

Checklist:

My code follows the style guidelines of this project
I have performed a self-review of my own code
My changes generate no new warnings
Any dependent changes have been merged and published in downstream modules

[rpardini]

k3 family...

[Grippy98]

Are you saying there's an issue with k3 for board family? Any current TI based device w/ AM6x series would fall under K3 normally.

[rpardini]

edge branch....

[Grippy98]

My intention is to keep it only to edge to simplify testing until it gets mainlined into both uboot and kernel and then I'll completely drop the custom beagle stuff in favor of K3. For K3, we're going to probably update it so you can pick either TI stable/edge or upstream stable/edge and leave it at that.

[Grippy98]

When defining a LINUXFAMILY, it expects a new kernel config so putting it under k3-beagle-edge which is going to be where I keep the source for PB2 and BeagleY (which I'll push next week) instead of calling it k3-pb2.

If you think this approach makes sense I'm good to keep it like this for now. This ultimately needs to be cleaned up once J722s and PB2 are upstreamed.