xen: Add module alias to autoload backend drivers

All the Xen backend drivers are assigned to a special bus type
xen-backend. This patch exports xen-backend:* names through modalias and
uevent to autoload them.

Signed-off-by: Bastian Blank <waldi@debian.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 2ed0b04..bd2f90c 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -393,7 +393,8 @@
 static ssize_t modalias_show(struct device *dev,
 			     struct device_attribute *attr, char *buf)
 {
-	return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype);
+	return sprintf(buf, "%s:%s\n", dev->bus->name,
+		       to_xenbus_device(dev)->devicetype);
 }
 
 struct device_attribute xenbus_dev_attrs[] = {