x86: compile error fix for smpboot.c

Without this patch, my link fails with:

arch/x86/kernel/built-in.o(.cpuinit.text+0x3c6e): In function `get_local_pda':
: undefined reference to `_cpu_pda'
arch/x86/kernel/built-in.o(.cpuinit.text+0x3cd1): In function `get_local_pda':
: undefined reference to `after_bootmem'
arch/x86/kernel/built-in.o(.cpuinit.text+0x3cec): In function `get_local_pda':
: undefined reference to `_cpu_pda'
make[2]: *** [.tmp_vmlinux1] Error 1

Caused by commit 766da892634694f795b18b9538407816896fc470
    x86: remove static boot_cpu_pda array v2
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/smpboot.c

@@ -816,6 +816,7 @@ static void __cpuinit do_fork_idle(struct work_struct *work)
 	complete(&c_idle->done);
 }
 
+#ifdef CONFIG_X86_64
 /*
  * Allocate node local memory for the AP pda.
  *
@@ -852,6 +853,7 @@ static int __cpuinit get_local_pda(int cpu)
 	cpu_pda(cpu) = newpda;
 	return 0;
 }
+#endif /* CONFIG_X86_64 */
 
 static int __cpuinit do_boot_cpu(int apicid, int cpu)
 /*