arm: remove remaining cannot_destroy_with_object_finalize_yet

arm: remove remaining cannot_destroy_with_object_finalize_yet

With commit ce5b1bbf624b ("exec: move cpu_exec_init() calls to
realize functions"), we can now remove all the
remaining cannot_destroy_with_object_finalize_yet as
unsafe references have been moved to cpu_exec_realizefn().
(tested with QOM command provided by commit 4c315c27).

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20170414083717.13641-2-lvivier@redhat.com>
Acked-by: Alistair Francis <alistair.francis@xilinx.com>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>