Revert 5fdf2d51

This reverts 5fdf2d51, except for one improved
log message.

Fixes #10613.

Checking if resume= is configured is a good idea, but it turns out we cannot do
it reliably:
- the code only supported boot options with sd-boot, and it's not very widely
  used. This means that for most systemd we could only check the current
  commandline, not the next one.
- Various systems resume without, e.g. Debian has
  /etc/initramfs-tools/conf.d/resume in the initramfs.

Making those checks better would be possible with enough effort, but there'll
be always new systems that boot in a slightly different way and we would need
to keep adding new cases. Longer term, we want to rely on autodetecting the
resume partition, and then checks like this will not be necessary at all. It is
quite clear from the number of bug reports that the number of poeple impacted
by this is quite high now, so let's just drop this.