kexec: Fix CONFIG_SMP=n compilation V2 (ia64)

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>