boards: Add support for PG23/PG28 Pro Kit

[janchri]

This PR adds support for two development kits from Silicon Labs:

• xG23-PK2504A
• xG28-PK2506A

For the xG23-PK2504A, RTT has been configured due to issues when accessing the console via EUSART0/1. Tested manually on basic samples (hello world, blinky, and button).

This PR builds on the work carried out for xg24_ek2703a and other ports from the dev Kit folder.

Depends on: zephyrproject-rtos/hal_silabs#95

[github-actions]

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[github-actions]

The following west manifest projects have changed revision in this Pull Request:

Name	Old Revision	New Revision	Diff
hal_silabs	janchri/hal_silabs@190a144	janchri/hal_silabs@e4e23d9 (main)	janchri/[email protected]

Additional metadata changed:

Name	URL	Submodules	West cmds	module.yml	Blobs
hal_silabs	✏

⛔ DNM label due to: 1 project with metadata changes

Note: This message is automatically posted and updated by the Manifest GitHub Action.

[nordicjm]

fix as per https://docs.zephyrproject.org/latest/contribute/style/devicetree.html there are multiple issues in all files in this PR, fix them all

[janchri]

I added the missing empty line between blocks. I use tab for idents. Am I missing more? Can I somehow start the code checking action by myself? I am really suprised that this ending issue/ms problem appeard.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
5.7% Duplication on New Code

See analysis details on SonarQube Cloud