[IA64] xen_domu_defconfig: fix build issues/warnings

- drivers/xen/events.c did not compile
- xen_setup_hook caused a modpost section warning
- the use of u64 (instead of unsigned long long) together with a %llu
  in drivers/xen/balloon.c caused a compiler warning

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

drivers/xen/balloon.c

@@ -513,7 +513,8 @@ static ssize_t show_target(struct sys_device *dev, struct sysdev_attribute *attr
 			      char *buf)
 {
 	return sprintf(buf, "%llu\n",
-		       (u64)balloon_stats.target_pages << PAGE_SHIFT);
+		       (unsigned long long)balloon_stats.target_pages
+		       << PAGE_SHIFT);
 }
 
 static ssize_t store_target(struct sys_device *dev,