net, hub: fix the indent in the comments

  Remove some redundant blanks in the comments of
net_hub_id_for_client().

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/net/hub.c b/net/hub.c
index be41301..3b2d1ff 100644
--- a/net/hub.c
+++ b/net/hub.c
@@ -256,7 +256,7 @@
 /**
  * Get the hub id that a client is connected to
  *
- * @id              Pointer for hub id output, may be NULL
+ * @id: Pointer for hub id output, may be NULL
  */
 int net_hub_id_for_client(NetClientState *nc, int *id)
 {