x86: nmi - unify die_nmi() interface

By slightly changing 32bit mode die_nmi() we may unify the
interface and make it common for both (32/64bit) modes

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: hpa@zytor.com
Cc: mingo@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>