Do not re-compress compressed kernel modules and firmware files

[Benjamin Drung]

initramfs-tools decompresses kernel modules and firmware files before putting them into the initramfs. This has several drawbacks:

* The compressed kernel modules and firmware files are probably compressed with a higher level. So recompressing them in the initramfs (default: zstd -1) will increase the size.
* Decompressing and compressing these files during mkinitramfs will take time
* The size of the decompressed initramfs will be bigger. That size is needed in memory during boot.

So put compressed kernel modules and firmware files in an uncompressed cpio instead. To make this change have an impact the files need to be shipped compressed:

* kernel modules: bug #2028568
* firmware files: bug #1942260

See https://lists.ubuntu.com/archives/ubuntu-devel/2023-July/042652.html and https://lists.ubuntu.com/archives/ubuntu-devel/2023-July/042707.html

[Launchpad Janitor (janitor)]

This bug was fixed in the package initramfs-tools - 0.142ubuntu8

---------------
initramfs-tools (0.142ubuntu8) mantic; urgency=medium

  [ Benjamin Drung ]
  * mkinitramfs:
    - Do not store intermediate main cpio archive
    - Put compressed kernel modules and firmware files in an uncompressed cpio
      (LP: #2028567)
  * Add support for zstd-compressed firmware
  * test: Ignore remaining systemd-udevd processes on arm64 as well
  * Update lintian overrides to format for lintian 2.116.3

  [ Loïc Minier ]
  * hook-functions: add stusb160x kernel module for Tegra IGX (LP: #2027636)

 -- Benjamin Drung <email address hidden> Wed, 26 Jul 2023 14:05:19 +0200