monitor: Add set_link arguments completion.

Make it possible to query all net clients without specifying an ID when calling
qemu_find_net_clients_except().

This also adds the add_completion_option() function which is to be used for
other commands completions as well.

Signed-off-by: Hani Benhabiles <[email protected]>
Reviewed-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Luiz Capitulino <[email protected]>
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 93fa534..3e7b29c 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1340,6 +1340,7 @@
         .params     = "name on|off",
         .help       = "change the link status of a network adapter",
         .mhandler.cmd = hmp_set_link,
+        .command_completion = set_link_completion,
     },
 
 STEXI