[S390] claw: add support for irq statistics

Add support for CLAW 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>

arch/s390/kernel/irq.c

@@ -40,6 +40,7 @@ static const struct irq_class intrclass_names[] = {
 	{.name = "TAP", .desc = "[I/O] Tape" },
 	{.name = "VMR", .desc = "[I/O] Unit Record Devices" },
 	{.name = "LCS", .desc = "[I/O] LCS" },
+	{.name = "CLW", .desc = "[I/O] CLAW" },
 	{.name = "NMI", .desc = "[NMI] Machine Check" },
 };