xen/xenfs: update xenfs_mount for new prototype

.mount now returns a struct dentry *.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
index f6339d1..990ee42 100644
--- a/drivers/xen/xenfs/super.c
+++ b/drivers/xen/xenfs/super.c
@@ -121,9 +121,9 @@
 	return rc;
 }
 
-static int xenfs_mount(struct file_system_type *fs_type,
-			int flags, const char *dev_name,
-			void *data)
+static struct dentry *xenfs_mount(struct file_system_type *fs_type,
+				  int flags, const char *dev_name,
+				  void *data)
 {
 	return mount_single(fs_type, flags, data, xenfs_fill_super);
 }