Xen options need to depend on XEN.
Also, add newline at end of file.

Without this patch you need to disable CONFIG_PM in order to
disable CPU hotplugging.
Signed-off-by: NChuck Ebbert <cebbert@redhat.com>
Acked-by Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>