EDIT: Don’t do this. See posts below.
You can considerably simplify that circuit as the black wire is an open collector NPN output.
Remove the optocoupler and resistors and connect the black wire directly to P12. Connect the 5V GND to the 3.3V GND if they do not have a common ground.
Leave your CC2530 configuration exactly the same.
The black wire will normally be open allowing the internal pull-up resistor to pull P12 to 3.3V. When active the NPN transistor black wire pulls this to ground. Exactly the same as your optocoupler was doing.