[S390] cio: Make ccw_device_register() static.

ccw_device_register() is only called from io_subchannel_register()
and io_subchannel_probe() and will never be called for possible
non-io subchannels.

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 94bdd4d..39c98f9 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -532,8 +532,7 @@
 
 /* this is a simple abstraction for device_register that sets the
  * correct bus type and adds the bus specific files */
-int
-ccw_device_register(struct ccw_device *cdev)
+static int ccw_device_register(struct ccw_device *cdev)
 {
 	struct device *dev = &cdev->dev;
 	int ret;