powerpc: Convert global "BAD" interrupt to per cpu spurious

I often get asked if BAD interrupts are really bad. On some boxes (eg
IBM machines running a hypervisor) there are valid cases where are
presented with an interrupt that is not for us. These cases are common
enough to show up as thousands of BAD interrupts a day.

Tone them down by calling them spurious. Since they can be a significant cause
of OS jitter, we may as well log them per cpu so we know where they are
occurring.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/hardirq.h b/arch/powerpc/include/asm/hardirq.h
index cd2d4be..3147a29 100644
--- a/arch/powerpc/include/asm/hardirq.h
+++ b/arch/powerpc/include/asm/hardirq.h
@@ -9,6 +9,7 @@
 	unsigned int timer_irqs;
 	unsigned int pmu_irqs;
 	unsigned int mce_exceptions;
+	unsigned int spurious_irqs;
 } ____cacheline_aligned irq_cpustat_t;
 
 DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
@@ -25,7 +26,4 @@
 extern u64 arch_irq_stat_cpu(unsigned int cpu);
 #define arch_irq_stat_cpu	arch_irq_stat_cpu
 
-extern u64 arch_irq_stat(void);
-#define arch_irq_stat		arch_irq_stat
-
 #endif /* _ASM_POWERPC_HARDIRQ_H */