[PV-ON-HVM] Fix evtchn of unbind_from_irqhandler()

When xm block-detach command was done on PV-ON-HVM, the response of
other disks was lost. It is because a wrong event channel was
invalidated when detaching it. Not the evtchn number but the irq
number is invalidated specifying it.

Signed-off-by: Takanori Kasai <kasai.takanori@jp.fujitsu.com>
Signed-off-by: Tomonari Horikoshi <t.horikoshi@jp.fujitsu.com>
Signed-off-by: Kazuhiro Suzuki <kaz@jp.fujitsu.com>

unmodified_drivers/linux-2.6/platform-pci/evtchn.c

@@ -223,7 +223,7 @@ void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 	evtchn = evtchn_from_irq(irq);
 
 	if (is_valid_evtchn(evtchn)) {
-		evtchn_to_irq[irq] = -1;
+		evtchn_to_irq[evtchn] = -1;
 		mask_evtchn(evtchn);
 		if (irq_evtchn[irq].close) {
 			struct evtchn_close close = { .port = evtchn };