Also set XEN_ATTACH mode in xen_init() to reflect the truth; not that
anyone ever cared before. It was *only* ever checked in xen_init_pv()
before.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>