Going from kernel snap #23(4.15.0-1032.34) to #25(4.15.0-1033.35), all kernel
modules were removed from initrd, breaking binaries that required fb to be setup
early during boot (e.g. bin/psplash in pi kernel snap core 18).
Fix that by adding back all fb kmods (and dependencies) to initrd.
Proposing for linux-snap/+git/bionic, master branch.