- if the land detector started before the mavlink module it won't have
   a valid message vehicle_land_detected message until published again

   The mapping of PX4_SPIDEV_ACCEL_MAG to PX4_SPIDEV_ICM is not
   a clean approach and the PX4_SPIDEV_MPU is already used by the
   mpu9250 leaving the only (and the correct) option to the use
   PX4_SPIDEV_ICM and make it map to the reused ACCEL_MAG_CS PC15
   as 206080D_CS

The mavlink message MOUNT_STATUS has been renamed to MOUNT_ORIENTATION.

This changes the Firmware code accordingly.

Thanks to Beat Küng for improved tuning.

Make it common with other boards

This is the file to set things related to the Intel Aero RTF.

For now it is only checking if there is a external HMC5883, if
necessary more compass should be added and probe.

AeroFC is updated by Aero board using the UART between AeroFC
and Aero board.

This script will copy firmware and px_uploader.py to Aero board and run
px_uploader.py with the correct paremeters. User only needs to have a
network connection (Ethernet over USB or WiFi) with Aero board to update
AeroFC firmware. The IP/hostname can be given by AERO_HOSTNAME
environment variable.

Right now it's only possible to use ttyS2 as the UART for connecting a
companion computer. Add a variable that can be set so other boards may
be better supported.

Or mixer load will fail

We export an "empty" table, but there's no protection when doing
ioctl().

So it just does rcin and does not try to do the other initializations.

As ASC use a non-standard UART for mavlink it is necessary check for
the board name and set SYS_AUTOSTART to initialize mavlink on the
right interface otherwise there is no way to change the SYS_AUTOSTART.

Correct set pin mux and removed unused interfaces.

MPU6500, MS5611 and HMC5883 only power on when GPIO_SENSORS_POWER is
set.

Battery voltage and current will be read in another way in future.

Like in bootloader, use the centered LED to show activity.

SPI bus 1 is the bus connected to MPU6500, so remove SPI bus 3 and 4.
Also remove everything else related to SPI that this board doesn't have.

Remove what's not used like SPI and UART ports, ADC, etc. Add UART5 and
I2C1 that are going to be used.

This also received contribution from
José Roberto de Souza <jose.souza@intel.com>.