kexec: Fix CONFIG_SMP=n compilation V2 (ia64)

Kexec support for 2.6.20 on ia64 does not build properly using a config
made up by CONFIG_SMP=n and CONFIG_HOTPLUG_CPU=n:

  CC      arch/ia64/kernel/machine_kexec.o
arch/ia64/kernel/machine_kexec.c: In function `machine_shutdown':
arch/ia64/kernel/machine_kexec.c:77: warning: implicit declaration of function `cpu_down'
  AS      arch/ia64/kernel/relocate_kernel.o
  CC      arch/ia64/kernel/crash.o
arch/ia64/kernel/crash.c: In function `kdump_cpu_freeze':
arch/ia64/kernel/crash.c:139: warning: implicit declaration of function `ia64_jump_to_sal'
arch/ia64/kernel/crash.c:139: error: `sal_boot_rendez_state' undeclared (first use in this function)
arch/ia64/kernel/crash.c:139: error: (Each undeclared identifier is reported only once
arch/ia64/kernel/crash.c:139: error: for each function it appears in.)
arch/ia64/kernel/crash.c: At top level:
arch/ia64/kernel/crash.c:84: warning: 'kdump_wait_cpu_freeze' defined but not used
make[1]: *** [arch/ia64/kernel/crash.o] Error 1
make: *** [arch/ia64/kernel] Error 2

Signed-off-by: Magnus Damm <magnus@valinux.co.jp>
Acked-by: Simon Horman <horms@verge.net.au>
Acked-by: Jay Lan <jlan@sgi.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

arch/ia64/kernel/crash.c

@@ -79,6 +79,7 @@ crash_save_this_cpu()
 	final_note(buf);
 }
 
+#ifdef CONFIG_SMP
 static int
 kdump_wait_cpu_freeze(void)
 {
@@ -91,6 +92,7 @@ kdump_wait_cpu_freeze(void)
 	}
 	return 1;
 }
+#endif
 
 void
 machine_crash_shutdown(struct pt_regs *pt)
@@ -132,11 +134,12 @@ kdump_cpu_freeze(struct unw_frame_info *info, void *arg)
 	atomic_inc(&kdump_cpu_freezed);
 	kdump_status[cpuid] = 1;
 	mb();
-	if (cpuid == 0) {
-		for (;;)
-			cpu_relax();
-	} else
+#ifdef CONFIG_HOTPLUG_CPU
+	if (cpuid != 0)
 		ia64_jump_to_sal(&sal_boot_rendez_state[cpuid]);
+#endif
+	for (;;)
+		cpu_relax();
 }
 
 static int

arch/ia64/kernel/machine_kexec.c

@@ -70,12 +70,14 @@ void machine_kexec_cleanup(struct kimage *image)
 
 void machine_shutdown(void)
 {
+#ifdef CONFIG_HOTPLUG_CPU
 	int cpu;
 
 	for_each_online_cpu(cpu) {
 		if (cpu != smp_processor_id())
 			cpu_down(cpu);
 	}
+#endif
 	kexec_disable_iosapic();
 }