ftrace: add notrace annotations for NMI routines

This annotates NMI functions with notrace. Some tracers may be able
to live with this, but some cannot. The safest is to turn it off,
it's not particularly interesting anyway.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>