Simplify getting sim PID
Simplify getting sim PID

Follow up of https://github.com/PX4/Firmware/pull/15206#pullrequestreview-436356707
acfloria/Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,krbeverx/Firmware,PX4/Firmware,krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,krbeverx/Firmware,acfloria/Firmware,PX4/Firmware,PX4/Firmware,acfloria/Firmware,acfloria/Firmware,acfloria/Firmware,krbeverx/Firmware,acfloria/Firmware,acfloria/Firmware,krbeverx/Firmware