Now that all compressed files get moved to the early uncompressed CPIO,
there is no need to recompress kernel modules and their firmware with a
weaker compression. I.e. Arch's kernel modules and firmware are
compressed with zstd at level `19`, while mkinitcpio defaults to zstd's
default level `3`.

Having the kernel decompress modules and firmware upon loading them,
instead of decompressing a larger initramfs image, also apparently
improves boot speed on some slower CPUs.

Co-authored-by: Eva Kurchatova <4163-lekkit@users.noreply.gitlab.archlinux.org>
Co-authored-by: Markus Weippert <markus@gekmihesg.de>