Cancel BUILD_BUG_ON check because it has not been defined at some kernel.h version.

Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>

diff -r 78de521ade9d tools/libxc/xc_pm.c
--- a/tools/libxc/xc_pm.c	Thu Dec 11 01:25:39 2008 +0800
+++ b/tools/libxc/xc_pm.c	Thu Dec 11 11:05:58 2008 +0800
@@ -25,7 +25,6 @@
 
 #include <errno.h>
 #include <curses.h>
-#include <linux/kernel.h>
 
 #include "xc_private.h"
 
@@ -255,10 +254,6 @@ int xc_get_cpufreq_para(int xc_handle, i
         memcpy(user_para->scaling_governor,
                 sys_para->scaling_governor, CPUFREQ_NAME_LEN);
 
-        /* copy to user_para no matter what cpufreq governor */
-        BUILD_BUG_ON(sizeof(((struct xc_get_cpufreq_para *)0)->u) !=
-                     sizeof(((struct xen_get_cpufreq_para *)0)->u));
-
         memcpy(&user_para->u, &sys_para->u, sizeof(sys_para->u));
     }