AP_InertialSensor: add support for BBBMINI, simple ArduPilot DIY Cape for the BeagleBone Black

libraries/AP_InertialSensor/AP_InertialSensor_MPU9250.cpp

@@ -288,6 +288,9 @@ bool AP_InertialSensor_MPU9250::update( void )
     // way up, and PWM pins on NavIO are at the back of the aircraft
     accel.rotate(ROTATION_ROLL_180_YAW_90);
     gyro.rotate(ROTATION_ROLL_180_YAW_90);
+#elif CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_BBBMINI
+    accel.rotate(ROTATION_ROLL_180);
+    gyro.rotate(ROTATION_ROLL_180);
 #endif
 
     _rotate_and_offset_gyro(_gyro_instance, gyro);