pmw3901: Adjust scale factor to match gyro data

src/drivers/optical_flow/pmw3901/PMW3901.cpp

@@ -324,8 +324,8 @@ PMW3901::RunImpl()
 		return;
 	}
 
-	delta_x = (float)_flow_sum_x / 500.0f;		// proportional factor + convert from pixels to radians
-	delta_y = (float)_flow_sum_y / 500.0f;		// proportional factor + convert from pixels to radians
+	delta_x = (float)_flow_sum_x / 385.0f;		// proportional factor + convert from pixels to radians
+	delta_y = (float)_flow_sum_y / 385.0f;		// proportional factor + convert from pixels to radians
 
 	optical_flow_s report{};
 	report.timestamp = timestamp;