AP_Compass: allows boards to define orientation of HMC5843

libraries/AP_Compass/AP_Compass.cpp

@@ -813,7 +813,11 @@ void Compass::_detect_backends(void)
     ADD_BACKEND(DRIVER_AK8963, AP_Compass_AK8963::probe_mpu9250(*this, 0),
                 AP_Compass_AK8963::name, false);
 #elif HAL_COMPASS_DEFAULT == HAL_COMPASS_HMC5843
-    ADD_BACKEND(DRIVER_HMC5883, AP_Compass_HMC5843::probe(*this, hal.i2c_mgr->get_device(HAL_COMPASS_HMC5843_I2C_BUS, HAL_COMPASS_HMC5843_I2C_ADDR)),
+#ifndef HAL_COMPASS_HMC5843_ROTATION
+# define HAL_COMPASS_HMC5843_ROTATION ROTATION_NONE
+#endif
+    ADD_BACKEND(DRIVER_HMC5883, AP_Compass_HMC5843::probe(*this, hal.i2c_mgr->get_device(HAL_COMPASS_HMC5843_I2C_BUS, HAL_COMPASS_HMC5843_I2C_ADDR),
+                                                          false, HAL_COMPASS_HMC5843_ROTATION),
                 AP_Compass_HMC5843::name, false);
 #elif HAL_COMPASS_DEFAULT == HAL_COMPASS_HMC5843_MPU6000
     ADD_BACKEND(DRIVER_HMC5883, AP_Compass_HMC5843::probe_mpu6000(*this),