This allows switching back and forth between 10 and 11 bit
code which prevents getting locked up in one or the other.
It also avoids a situation that can cause an infinite
recursion.
This changeset is cherry-picked from TauLabs (b7eaf87502085666d9738ae16c66170f187f3981).
Thanks to Taulabs for improving OpenPilot's DSM autodetect feature.