[S390] ctc: add support for irq statistics

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

Signed-off-by: Heiko Carstens <heiko.carstens@de.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 2d5943c..8c79f94 100644
--- a/arch/s390/include/asm/irq.h
+++ b/arch/s390/include/asm/irq.h
@@ -24,6 +24,7 @@
 	IOINT_VMR,
 	IOINT_LCS,
 	IOINT_CLW,
+	IOINT_CTC,
 	NMI_NMI,
 	NR_IRQS,
 };