Drop 40rhcos-fips dracut module

[jlebon]

See https://fedoraproject.org/wiki/Changes/RemoveFipsModeSetup. The idea there is that the fips=1 karg becomes the source of truth. This is something that should work in image-mode RHEL/CentOS Stream already and we just inherit from that. On the MCO side, long-term on-cluster layering should do the equivalent of https://gitlab.com/fedora/bootc/examples/-/blob/main/fips/Containerfile?ref_type=heads to enable it at layering time. Short-term, at the very least, we should be able to get rid of this bit since calling fips-mode-setup should no longer be necessary. See also conversation in coreos/ignition#1323.