xen/events: support threaded irqs for interdomain event channels

Export bind_interdomain_evtchn_to_irq() so drivers can use threaded
interrupt handlers with:

 irq = bind_interdomain_evtchn_to_irq(remote_dom, remote_port);
 if (irq < 0)
     /* error */
 ret = request_threaded_irq(...);

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/include/xen/events.h b/include/xen/events.h
index 8bee7a7..5321cd9 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -28,6 +28,8 @@
 			   unsigned long irqflags,
 			   const char *devname,
 			   void *dev_id);
+int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
+				   unsigned int remote_port);
 int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
 					  unsigned int remote_port,
 					  irq_handler_t handler,