[ISSUE] Raspberry Pi images use powersave governor by default

[beadleha <beadleha@users.noreply.github.com>]

[-- Attachment #1: Type: text/plain, Size: 2023 bytes --]

New issue by beadleha on void-packages repository

https://github.com/void-linux/void-packages/issues/34049

Description:
The mainline Linux kernel uses `schedutil` as the default cpu frequency governor for both arm and arm64 since version 5.9, and now uses it by default on most other platforms as well. Void for x86/x86_64 currently use `schedutil` by default because of this. However, the Raspberry Pi kernel fork uses `powersave` instead, and then overrides it using the cpufreq package in Raspberry Pi OS. The developers do not seem inclined to change it since the default setting is overridden by Raspberry Pi OS anyway.

Void Linux does not initially override the default setting, so the default governor that the kernel is compiled with is the one that is used. This makes the system extremely slow until the user overrides the kernel's default setting.

My proposal is to add a sed command to the build templates make the kernel follow the default used in mainline kernels. This seems simpler than adding the cpufreq package to the base images. I believe the change would only affect the templates for `rpi-kernel`, `rpi3-kernel`, and `rpi4-kernel`.

And the change could look like this:
    # Set default frequency governor to match mainline kernel
    sed -i 's/CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE=y/CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL=y/g' "$defconfig"

Let me know what you think.

### System

* xuname:  
Void 5.10.52_1 aarch64 Unknown notuptodate rFF
* package:  
rpi4-kernel-5.10.52_1

### Expected behavior
Linux mainline kernel uses `schedutil` by default, including on arm and arm64.
Void generally follows this default from upstream.
I would expect the default governor for Void to also be `schedutil` on my Raspberry Pi.

### Actual behavior
Void for Raspberry Pi uses `powersave` and the system is sluggish until the default is overridden.

### Steps to reproduce the behavior
Check default cpu governor on Void for Raspberry Pi. Compare to default for x86 and x86_64.