p2p/enode: fix method doc (#23115)

This is an obvious spelling error
Co-authored-by: liuyaxiong <liuyaxiong@inspur.com>

p2p/enode/node.go

@@ -121,7 +121,7 @@ func (n *Node) UDP() int {
 	return int(port)
 }
 
-// UDP returns the TCP port of the node.
+// TCP returns the TCP port of the node.
 func (n *Node) TCP() int {
 	var port enr.TCP
 	n.Load(&port)