Reasons it may not be committed:
It's for a single plugin, on a single player. This means it's of minimal interest among devs, because most of them have plenty of things on their plate already without taking the time to make sure the patch is coded according to Rockbox guidelines and doesn't break anything else.
If the author of the patch perhaps went to IRC and asked what's holding it from being committed, they might be able to get it added. Which entry in the tracker is it, exactly?