[S390] chsc_sch: add support for irq statistics

Add support for CHSC I/O interrupt statistics in /proc/interrupts.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/irq.h b/arch/s390/include/asm/irq.h
index 1f68605..eadfa9f 100644
--- a/arch/s390/include/asm/irq.h
+++ b/arch/s390/include/asm/irq.h
@@ -28,6 +28,7 @@
 	IOINT_CLW,
 	IOINT_CTC,
 	IOINT_APB,
+	IOINT_CSC,
 	NMI_NMI,
 	NR_IRQS,
 };