Nothing good will be achieved by telling your co-workers you heard them gossiping. It will just create awkwardness at the office. In fact, it doesn't really matter if they think you are a "control freak." What matters is, how successful you are at what you do and how good of a leader you are. Convene a meeting with the co-workers
that you supervise with an agenda of asking them for suggestions on how you can help them do their job better and making your company more efficient. Be open to their suggestions and they will appreciate that you value their opinions. But remember, people will often think their boss is bossy. You can't make everyone like you, but you can be a strong and inspiring leader.