[S390] irq: external interrupt code passing

The external interrupt handlers have a parameter called ext_int_code.
Besides the name this paramter does not only contain the ext_int_code
but in addition also the "cpu address" (POP) which caused the external
interrupt.
To make the code a bit more obvious pass a struct instead so the called
function can easily distinguish between external interrupt code and
cpu address. The cpu address field however is named "subcode" since
some external interrupt sources do not pass a cpu address but a
different parameter (or none at all).

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 e8fcd92..b17c42d 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -532,7 +532,7 @@
 static DEFINE_SPINLOCK(pfault_lock);
 static LIST_HEAD(pfault_list);
 
-static void pfault_interrupt(unsigned int ext_int_code,
+static void pfault_interrupt(struct ext_code ext_code,
 			     unsigned int param32, unsigned long param64)
 {
 	struct task_struct *tsk;
@@ -545,7 +545,7 @@
 	 * in the 'cpu address' field associated with the
          * external interrupt. 
 	 */
-	subcode = ext_int_code >> 16;
+	subcode = ext_code.subcode;
 	if ((subcode & 0xff00) != __SUBCODE_MASK)
 		return;
 	kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++;