[PATCH] Fix s390 fallout from PR11271 patch

[Eric Botcazou]

> If this code were to be enabled for the thumb case, I think we'd end up
> with invalid output.  The reason being that the code would attempt to
> generate a sum of the stack pointer and another register, but that's
> invalid: one of the reasons the stack pointer isn't classed as a base
> register is because this mode of addressing is not supported for stack
> accesses.

Okay.  But the comment is very misleading.

-- 
Eric Botcazou