[PATCH] kdump x86_64 nmi event notification fix

After a crash we should wait for NMI IPI event and not for external NMI or
NMI watchdog tick.

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>