[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>

arch/s390/kernel/irq.c

@@ -53,6 +53,7 @@ static const struct irq_class intrclass_names[] = {
 	{.name = "CLW", .desc = "[I/O] CLAW" },
 	{.name = "CTC", .desc = "[I/O] CTC" },
 	{.name = "APB", .desc = "[I/O] AP Bus" },
+	{.name = "CSC", .desc = "[I/O] CHSC Subchannel" },
 	{.name = "NMI", .desc = "[NMI] Machine Check" },
 };