[wide-int] Rename a function to match its type

[Mike Stump]

On Nov 9, 2013, at 2:16 AM, Richard Sandiford <rdsandiford@googlemail.com> wrote:
> wide_int_type_size_in_bits returns an offset_int (previously an addr_int)
> rather than a wide_int, so this patch renames it accordingly.

> OK to install?

Ok.