[S390] cio: Make some structures and a function static.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index a23ff58..a8b373f 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -129,7 +129,7 @@
 static void io_subchannel_ioterm(struct device *);
 static void io_subchannel_shutdown(struct subchannel *);
 
-struct css_driver io_subchannel_driver = {
+static struct css_driver io_subchannel_driver = {
 	.subchannel_type = SUBCHANNEL_TYPE_IO,
 	.drv = {
 		.name = "io_subchannel",
@@ -546,7 +546,7 @@
 	.attrs = ccwdev_attrs,
 };
 
-struct attribute_group *ccwdev_attr_groups[] = {
+static struct attribute_group *ccwdev_attr_groups[] = {
 	&ccwdev_attr_group,
 	NULL,
 };