autossh incompatibility with dropbear -y

[Steve Newcomb]

I'm using OpenWRT.  My router, whose IP address changes unpredictably,
makes its ssh-listening port available on another host running at a
stable IP address, using autossh/dropbear to create a reverse channel.

Sometimes the host's key changes from time to time, which can stop the
autossh process at a prompt (to nobody) to decide what to do about the
change.

Ordinary OpenSSH has a StrictHostKeyChecking option which can be used to
bypass the so-called "ask" prompt and just make the connection regardless.

By reading the source, I learned that Dropbear's ssh client evidently
has a similar feature, the "-y" invocation option.  But I can't pass the
-y to it via autossh because autossh doesn't approve of it.  Dropbear's
ssh client also does not offer a config file utility, AFAIK.
Dropbear evidently ignores all -o options, too; they wind up in a bit
bucket called something like "dummy".

Does anybody know the answer, short of editing/recompiling autossh so it
won't be so persnickety and just get out of the way?

Steve Newcomb