ACPI: add /sys/firmware/acpi/interrupts/sci_not counter

This counter may prove useful in debugging some
spurious interrupt issues seen in the field.

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index d59f08e..d916bea 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -353,8 +353,10 @@
 	if (handled) {
 		acpi_irq_handled++;
 		return IRQ_HANDLED;
-	} else
+	} else {
+		acpi_irq_not_handled++;
 		return IRQ_NONE;
+	}
 }
 
 acpi_status