[S390] 3215: add support for irq statistics

Add support for 3215 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 082ef0c..d52533d 100644
--- a/arch/s390/include/asm/irq.h
+++ b/arch/s390/include/asm/irq.h
@@ -18,6 +18,7 @@
 	IOINT_QAI,
 	IOINT_QDI,
 	IOINT_DAS,
+	IOINT_C15,
 	NMI_NMI,
 	NR_IRQS,
 };