bfd: use default coff_write_object_contents for XCOFF64

[Alan Modra]

On Tue, Feb 16, 2021 at 09:55:27AM +0000, CHIGOT, CLEMENT wrote:
> Hi, 
> 
> There is no needed for XCOFF64 to have its own write_object_contents.
> 
> ChangeLog:
> 2020-10-26  Clément Chigot  <clement.chigot@atos.net>
> 
>         * bfd/coff64-rs6000.c (xcoff64_write_object_contents): Remove.
>         * bfd/coffcode.h (coff_write_object_contents): Add
>         bfd_mach_ppc_620 support for o_cputype field.  Avoid creating
>         an empty a.out header for XCOFF64.

Looks good to me.  I'll commit this when the copyright assignment is
done.

-- 
Alan Modra
Australia Development Lab, IBM