Removes the calibration on startup, as these values were overwritten by
the system calibration values anyway.
So the only difference is that if all calibration scales were equal to 1,
the driver startup would have failed.
* 8 kHz gyro, 4 kHz accel
* DLPF disabled
* scheduled using data ready interrupts
* FIFO is emptied at 1 kHz by default, but can adjusted via IMU_GYRO_RATEMAX from 250 Hz - 2000 kHz.
* On both px4_fmu-v4 and px4_fmu-v4pro the secondary IMU is an mpu9250 with the same driver
-moved rc.mavlink to the boards optional rc additions (now it's called rc.board_mavlink) to handle board specific mavlink needs (mavlink over usb, ethernet, additional streams, etc.)
-mavlink module will be responsible to usb defaults, therefore less args are needed to be passed to mavlink module if one wants to use mavlink over usb.
-the way to check if connection is usb is by it's designated variable and not by config mode.