[S390] cio: make wait_events interruptible

Make the potentially long blocking wait_event's used by the cio
settle mechanism interruptible.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/css.h b/drivers/s390/cio/css.h
index e05525d..325d813 100644
--- a/drivers/s390/cio/css.h
+++ b/drivers/s390/cio/css.h
@@ -95,7 +95,7 @@
 	int (*freeze)(struct subchannel *);
 	int (*thaw) (struct subchannel *);
 	int (*restore)(struct subchannel *);
-	void (*settle)(void);
+	int (*settle)(void);
 	const char *name;
 };