pkg/oonf_api: add avr8 and msp430 arch to features blacklist

[aabadie]

Contribution description

This allows to drop the BOARD_BLACKLIST in the tests/nhdp application because nhdp module depends on the oonf_api package.

Testing procedure

• a green Murdock
• make -C tests/nhdp info-boards-supported should return the same list of boards

Issues/PRs references

Follow-up of #12608

[miri64]

ACK. Output of make -C tests/nhdp/ --no-print-directory info-boards-supported is identical

$ git checkout master && make -C tests/nhdp/ --no-print-directory info-boards-supported | sha1sum
Already on 'master'
Your branch is up to date with 'upstream/master'.
35fbb308a14d125da98db9ce020056d71e0d3389  -
$ git pr upstream 12644 && make -C tests/nhdp/ --no-print-directory info-boards-supported | sha1sum
From git://github.com/RIOT-OS/RIOT
 * branch                  refs/pull/12644/head -> FETCH_HEAD
Note: checking out 'FETCH_HEAD'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b <new-branch-name>

HEAD is now at bf1b6b6f9c tests/nhdp: remove useless BOARD_BLACKLIST
35fbb308a14d125da98db9ce020056d71e0d3389  -

[miri64]

Just hit the green button, when Murdock is happy :-)

[aabadie]

Thanks for reviewing @miri64 :)