Committed: fix build error for cris-*-* due to rtx canonicalization change

[Eric Botcazou]

> I think there are going to be many more of these assumptions; I don't
> like at all that hunk of rtlanal.c and I think it should be reverted for
> now.

Agreed.

Peter, please revert the rtlanal.c bit for now, its effect on canonicalization 
are disruptive and would need to be evaluated on more architectures.  TIA.

-- 
Eric Botcazou