Bump buildroot to 2023.02-rc2 (#2374)

* Update config for Buildroot 2023.02

* Use Buildroot's version of the rtl8821cu package

Buildroot provides a newer driver for the RTL8821CU based chipsets
provided by https://github.com/morrownr/8821cu-20210118.

* Pass argument when verifying partition table

This also avoids running into a segmentation fault in the current
version of sgdisk.

* Remove obsolte GRUB2/NetworkManager patches

* Bump buildroot

* buildroot 90aa1a6daa...4832525e6c (4596):
  > package/runc: add support for CGroup device permission updates
  > package/network-manager: fix build with -Dmodem_manager=false
  > package/dbus-broker: bump to release 33
  > package/iptables: Allow to use iptables with nf_tables backend
  > package/brcmfmac_sdio-firmware-rpi: bump to latest version
  > package/linux-firmware: Deploy fewer Intel WiFi 22000 series variants
  > package/linux-firmware: Add more Intel WiFi 22000 series variants
  > package/linux-firmware: Add Broadcom BNX2 firmware
  > package/rpi-firmware: bump version to 1.20230106
  > Update for 2023.02-rc2

* Use Ubuntu 22.04 for CI checks

* Bump xe-guest-utilities to 7.33.0

* Remove unnecessary shellcheck ignore for xe-guest-utilities

* Address new buildroot check-packages issues

buildroot-external/scripts/hdd-image.sh

@@ -171,7 +171,7 @@ function _create_disk_gpt() {
 
     ##
     # Write Images
-    sgdisk -v
+    sgdisk -v "${hdd_img}"
     dd if="${boot_img}" of"=${hdd_img}" conv=notrunc,sparse bs=512 seek="${boot_offset}"
     dd if="${kernel_img}" of="${hdd_img}" conv=notrunc,sparse bs=512 seek="${kernel_offset}"
     dd if="${rootfs_img}" of="${hdd_img}" conv=notrunc,sparse bs=512 seek="${rootfs_offset}"