systemd: postmarketos-base-systemd: manually include kmod-libs in initramfs...

systemd: postmarketos-base-systemd: manually include kmod-libs in initramfs for systemd-udevd (MR 5340)

As systemd v256 switched to dlopen for a bunch of dependencies
(specified in a custom format), this is no longer auto-detected
by either abuild or boot-deploy. So we include kmod manually for udevd
to work correctly.

This fixes the "no screen" issue on pine64-pinephone.
[ci:skip-build]: already built successfully in CI