AP_Compass: use IST8310 and HMC5883 as external mags

libraries/AP_Compass/AP_Compass.cpp

@@ -763,6 +763,10 @@ void Compass::_detect_backends(void)
 #elif HAL_COMPASS_DEFAULT == HAL_COMPASS_AERO
     ADD_BACKEND(DRIVER_BMM150, AP_Compass_BMM150::probe(*this, hal.i2c_mgr->get_device(HAL_COMPASS_BMM150_I2C_BUS, HAL_COMPASS_BMM150_I2C_ADDR)),
                 AP_Compass_BMM150::name, false);
+    ADD_BACKEND(DRIVER_HMC5883, AP_Compass_HMC5843::probe(*this, hal.i2c_mgr->get_device(HAL_COMPASS_HMC5843_I2C_BUS, HAL_COMPASS_HMC5843_I2C_ADDR), true),
+                AP_Compass_HMC5843::name, true);
+    ADD_BACKEND(DRIVER_IST8310, AP_Compass_IST8310::probe(*this, hal.i2c_mgr->get_device(HAL_COMPASS_IST8310_I2C_BUS, HAL_COMPASS_IST8310_I2C_ADDR),
+                                                          true, ROTATION_PITCH_180_YAW_90), AP_Compass_IST8310::name, true);
 #elif CONFIG_HAL_BOARD == HAL_BOARD_LINUX && CONFIG_HAL_BOARD_SUBTYPE != HAL_BOARD_SUBTYPE_LINUX_NONE
     ADD_BACKEND(DRIVER_HMC5883, AP_Compass_HMC5843::probe(*this, hal.i2c_mgr->get_device(HAL_COMPASS_HMC5843_I2C_BUS, HAL_COMPASS_HMC5843_I2C_ADDR)),
                 AP_Compass_HMC5843::name, false);