xen: Module autoprobing support for frontend drivers

Add module aliases to support autoprobing modules
for xen frontend devices.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 7483d45b..b3fa27e 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1809,3 +1809,4 @@
 
 MODULE_DESCRIPTION("Xen virtual network device frontend");
 MODULE_LICENSE("GPL");
+MODULE_ALIAS("xen:vif");