output drivers: init SmartLock after exit_and_cleanup

This fixes an invalid memory access when exiting the module:
exit_and_cleanup destroys the object, but lock_guard is destructed after
and accesses the lock.

src/drivers/tap_esc/TAP_ESC.cpp

@@ -329,8 +329,6 @@ bool TAP_ESC::updateOutputs(bool stop_motors, uint16_t outputs[MAX_ACTUATORS], u
 
 void TAP_ESC::Run()
 {
-	SmartLock lock_guard(_lock);
-
 	if (should_exit()) {
 		ScheduleClear();
 		_mixing_output.unregister();
@@ -339,6 +337,8 @@ void TAP_ESC::Run()
 		return;
 	}
 
+	SmartLock lock_guard(_lock);
+
 	// push backup schedule
 	ScheduleDelayed(20_ms);