[S390] cio: remove subchannel_add_files()

subchannel_add_files() no longer exists, remove from header.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

drivers/s390/cio/css.h

@@ -191,6 +191,5 @@ int sch_is_pseudo_sch(struct subchannel *);
 
 extern struct workqueue_struct *slow_path_wq;
 
-int subchannel_add_files (struct device *);
 extern struct attribute_group *subch_attr_groups[];
 #endif