simulator_mavlink: fix type passed to param_get()

src/modules/simulator/simulator_mavlink.cpp

@@ -1106,8 +1106,9 @@ int Simulator::publish_flow_topic(mavlink_hil_optical_flow_t *flow_mavlink)
 	flow.quality = flow_mavlink->quality;
 
 	/* rotate measurements according to parameter */
-	enum Rotation flow_rot;
-	param_get(param_find("SENS_FLOW_ROT"), &flow_rot);
+	int32_t flow_rot_int;
+	param_get(param_find("SENS_FLOW_ROT"), &flow_rot_int);
+	const enum Rotation flow_rot = (Rotation)flow_rot_int;
 
 	float zeroval = 0.0f;
 	rotate_3f(flow_rot, flow.pixel_flow_x_integral, flow.pixel_flow_y_integral, zeroval);