x86: Eliminate irq_mis_count counted in arch_irq_stat

x86: Eliminate irq_mis_count counted in arch_irq_stat

commit f7b0e1055574ce06ab53391263b4e205bf38daf3 upstream.

With the current implementation, kstat_cpu(cpu).irqs_sum is also
increased in case of irq_mis_count increment.

So there is no need to count irq_mis_count in arch_irq_stat,
otherwise irq_mis_count will be counted twice in the sum of
/proc/stat.

Reported-by: Liu Chuansheng <chuansheng.liu@intel.com>
Signed-off-by: Li Fei <fei.li@intel.com>
Acked-by: Liu Chuansheng <chuansheng.liu@intel.com>
Cc: tomoki.sekiyama.qu@hitachi.com
Cc: joe@perches.com
Link: http://lkml.kernel.org/r/1366980611.32469.7.camel@fli24-HP-Compaq-8100-Elite-CMT-PC
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>