CLEANUP: cfgparse: cascade the warnif_misplaced_* rules

CLEANUP: cfgparse: cascade the warnif_misplaced_* rules

There are 8 functions each repeating what another does and adding one
extra test. We used to have some copy-paste issues in the past due to
this. Instead we now make them simply rely on the previous one and add
the final test. It's much better and much safer. The functions could
be moved to inlines but they're used at a few other locations only,
it didn't make much sense in the end.