xen/acpi: Move the xen_running_on_version_or_later function.

As on ia64 builds we get:
include/xen/interface/version.h: In function 'xen_running_on_version_or_later':
include/xen/interface/version.h:76: error: implicit declaration of function 'HYPERVISOR_xen_version'

We can later on make this function exportable if there are
modules using part of it. For right now the only two users are
built-in.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index 6a198e4..6170abd 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -29,4 +29,5 @@
 			       unsigned long mfn, int nr,
 			       pgprot_t prot, unsigned domid);
 
+bool xen_running_on_version_or_later(unsigned int major, unsigned int minor);
 #endif /* INCLUDE_XEN_OPS_H */