[reggen] Promote missing CM annotation warning to error

Fixes lowRISC#10071

Signed-off-by: Michael Schaffner <[email protected]>

util/reggen/countermeasure.py

@@ -207,9 +207,8 @@ def check_annotation_list(what: str,
 
  # Is there anything in the Hjson that isn't described in the RTL?
  for name in hjson_set - rtl_set:
- log.warning("Countermeasure {} is referenced in the Hjson of the "
- "{}, but doesn't appear in the RTL."
- .format(name, what))
-
- # TODO(#10071): Once all designs are annotated, generate a RuntimeError
- # if we saw anything in the loop above.
+ log.error("Countermeasure {} is referenced in the Hjson of the "
+ "{}, but doesn't appear in the RTL."
+ .format(name, what))
+ raise RuntimeError('One or more unknown countermeasures '
+ 'are not annotated in RTL.')