Sorry, don't have much time these days, so excuse my sparse reply.
- You should read https://openwrt.org/submitting-patches as your patch is very likely going to be rejected because it doesn't contain necessary formalities, like subject, description, signed-off-by etc.
- AFAIK you don't need to be subscribed to openwrt-devel@ to send patches or get responses to your patches/emails
- Your patch is not lost, you need to be patient as the review resources are scarce, feel free to reply to that email with "ping" if you don't get response in more then 30-45 days, it's OK