tools: ratbagctl: kill an infinite loop in parsing

Calling "ratbagctl profile -t" resulted in an infinite loop because it
tried again and again to parse "-t" in the profile

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>

tools/ratbagctl.in

@@ -1300,8 +1300,9 @@ class RatbagParserRoot(object):
             pr_debug(ns, "<<< {}: {} | {}".format(child.type, child.name, rest))
 
         while subparser:
+            old_rest = rest
             ns, rest = subparser.parse_known_args(rest, namespace=ns)
-            if not rest:
+            if not rest or old_rest == rest:
                 break
             pr_debug(ns, ns, rest)
             try: