kprobes, x86: Disable irqs during optimized callback

Disable irqs during optimized callback, so we dont miss any in-irq kprobes.

The following commands:

 # cd /debug/tracing/
 # echo "p mutex_unlock" >> kprobe_events
 # echo "p _raw_spin_lock" >> kprobe_events
 # echo "p smp_apic_timer_interrupt" >> ./kprobe_events
 # echo 1 > events/enable

Cause the optimized kprobes to be missed. None is missed
with the fix applied.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20110511110613.GB2390@jolsa.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>