xen: make CONFIG_XEN_SAVE_RESTORE depend on CONFIG_XEN

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: Chuck Ebbert <cebbert@redhat.com>
Acked-by Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>