kernel/cpu.c: delete deprecated definition in cpu_up()

Additional_cpus is only supported for IA64 now.  X86_64 should not be
included.

Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/cpu.c

@@ -338,7 +338,7 @@ int __cpuinit cpu_up(unsigned int cpu)
 	if (!cpu_possible(cpu)) {
 		printk(KERN_ERR "can't online cpu %d because it is not "
 			"configured as may-hotadd at boot time\n", cpu);
-#if defined(CONFIG_IA64) || defined(CONFIG_X86_64)
+#if defined(CONFIG_IA64)
 		printk(KERN_ERR "please check additional_cpus= boot "
 				"parameter\n");
 #endif