[IA64] xen_domu build fix

arch/ia64/xen/xen_pv_ops.c:156: error: xen_init_ops causes a section type conflict
arch/ia64/xen/xen_pv_ops.c:340: error: xen_iosapic_ops causes a section type conflict

Signed-off-by: Tony Luck <tony.luck@intel.com>