input: fix stack overflow when checking for abort cmd

This can happen when the input stream is somehow blocking on network,
and the user still send input in one way or another, and one of the
commands is a compound command ("cmd a ; cmd b").

input/cmd_list.c

@@ -276,7 +276,7 @@ bool mp_input_is_abort_cmd(struct mp_cmd *cmd)
     if (cmd->id == MP_CMD_COMMAND_LIST) {
         for (struct mp_cmd *sub = cmd->args[0].v.p; sub; sub = sub->queue_next)
         {
-            if (mp_input_is_abort_cmd(cmd))
+            if (mp_input_is_abort_cmd(sub))
                 return true;
         }
     }