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

[Paolo Bonzini]

Eric Botcazou wrote:
>> 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

(I probably sounded more aggravated than necessary.  I actually noticed 
that hunk being posted because I'm on the Cc for PR28690, but I had no 
time to review the patch -- sorry Peter).

Paolo