[S390] irqstats: fix counting of pfault, dasd diag and virtio irqs

pfault, dasd diag and virtio all use the same external interrupt number.
The respective interrupt handlers decide by the subcode if they are
meant to handle the interrupt.
Counting is currently done before looking at the subcode which means
each handler counts an interrupt even if it is not handling it.
Fix this by moving the kstat code after the code which looks at the
subcode.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 4cf85fe..ab98813 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -543,7 +543,6 @@
 	struct task_struct *tsk;
 	__u16 subcode;
 
-	kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++;
 	/*
 	 * Get the external interruption subcode & pfault
 	 * initial/completion signal bit. VM stores this 
@@ -553,6 +552,7 @@
 	subcode = ext_int_code >> 16;
 	if ((subcode & 0xff00) != __SUBCODE_MASK)
 		return;
+	kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++;
 
 	/*
 	 * Get the token (= address of the task structure of the affected task).