feat: add gpio-pinctrl extension for Intel Apollo Lake

[srgvg]

Summary

Add gpio-pinctrl extension that provides Intel GPIO/Pinctrl kernel modules for Apollo Lake platforms:

• pinctrl-intel.ko - Intel pinctrl core driver
• pinctrl-broxton.ko - Intel Apollo Lake (Broxton) pinctrl driver

Use Case

Enable GPIO access on Intel Apollo Lake platforms (INT3452 ACPI device), such as the Mitac MB1 industrial board. This allows hardware control applications to interact with GPIO pins from userspace using libgpiod via /dev/gpiochip* devices.

Dependencies

This extension requires kernel config options enabled in siderolabs/pkgs:

• PR: feat: enable Intel GPIO/Pinctrl kernel modules pkgs#1378

Usage

machine:
  install:
    extensions:
      - image: ghcr.io/siderolabs/gpio-pinctrl:<version>
  kernel:
    modules:
      - name: pinctrl-intel
      - name: pinctrl-broxton

Test Plan

• Extension builds successfully
• Contains correctly signed kernel modules
• Passes extension-validator checks
• Modules load on Apollo Lake hardware
• /dev/gpiochip* devices created
• GPIO access works via libgpiod