RFA: Fix crx --enable-werror-always build

[Joern Rennecke]

Quoting Richard Henderson <rth@redhat.com>:

> In the crx case, the un-wrapping of the subreg isn't saved back
> into the crx_address structure, and so the subreg will make it to
>
>       if (address.base && !REGNO_OK_FOR_BASE_P (REGNO (address.base)))
>
> which ought to ICE due to REGNO applied to SUBREG.  Which probably
> will never happen, since this only happens for strict, and I expect
> that subregs of hard regs are resolved by now.

cleanup_subreg_operands runs at the end of reload, but during reload you
might still see subregs.

> That said, a more correct patch seems like it would be like this:

Yes, that makes sense.
Although the one thing that stayed the same for crx_addr_reg_p - its name -
doesn't fit as well anymore.