x86-32, hibernate: Enable CONFIG_ARCH_HIBERNATION_HEADER on 32bit system

Enable CONFIG_ARCH_HIBERNATION_HEADER for 32bit system so that

1. arch_hibernation_header_save/restore() are invoked across
   hibernation on 32bit system.

2. The checksum handling as well as 'magic' number checking
   for 32bit system are enabled.

Controlled by CONFIG_X86_64 in hibernate.c

Signed-off-by: Zhimin Gu <kookoo.gu@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>