qapi: Convert migrate_set_downtime

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
diff --git a/hmp-commands.hx b/hmp-commands.hx
index e48c2ca..6ba694d 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -801,8 +801,7 @@
         .args_type  = "value:T",
         .params     = "value",
         .help       = "set maximum tolerated downtime (in seconds) for migrations",
-        .user_print = monitor_user_noop,
-        .mhandler.cmd_new = do_migrate_set_downtime,
+        .mhandler.cmd = hmp_migrate_set_downtime,
     },
 
 STEXI