kernel flavour rpi-def not available for armh.

This reverts commit 3e7b8d29.
No need to assign a browser in this feature. This feature used
actually for all aarch64, armh SBC.

Playing FullHD video with YouTube on Raspberry PI 4 in Firefox-ESR
starting with version 91 occurs with strong delays.
https://bugzilla.altlinux.org/41486
In the chromium problem is not observed.

At the moment rpi-def is LTS 5.10 rpi-un is 5.12
Revert "arm-rpi4: Use rpi-un kernel by default"

This reverts commit 857bf72c.

use/arm-rpi4 is now used to improve Raspberry Pi support in
universal rootfs with u-boot.

The Raspberry Pi 4 has hardware acceleration, there is no need to
use special programs.
bluetooth is needed only on a desktop.

While this argument can only have one "EFI" value.
Thus, the problem of building an image for Raspberry Pi on armh,
where there is no grub-efi, was solved.

This is need to working bluetooth with GUI

If there is no Ethernet connection, RPi4 loading stops for 2 minutes.

The feature фкь-кзш4 is available for armh now.

rpi4-boot-nouboot-filetrigger updates
files of kernel, initrd, dtb, cmdline.txt, config.txt
on FAT when updating kernel

rpi4-boot-uboot-filetrigger updates
files of u-boot and firmware
on FAT when updating u-boot

Switch of boot mode for Raspberry Pi 4
In Alt, it is customary to load the kernel, dtb and initrd
using u-boot and configuration in extlinux.conf.
Firmware Raspberry Pi 4 loads and modifies dtb
according to config.txt configuration.
U-boot doesn't.
The scripts in this package allow you to switch boot modes:
Firmware loads the kernel, dtb, and initrd. U-boot is not used.
Firmware loads dtb. U-boot loads the kernel and initrd.
U-boot loads the kernel, dtb, and initrd.

Raspberry Pi 3/4 simply TUI switch between HDMI and 3,5mm
headphone jack audio output.