- It takes the input from the constrains from the active flight task

- An new message is created just for the landing gear
- The old logic is repalaced by publishing this new topic

Keeps things more modular.

 * fixes parameters on Snapdragon

* added a parameter for enabled the smart battery
* start tel1 and tel2 at 921600 and max rate
* turned up the max tx rate on mavlink streams for telem1 and telem2
* turned off mavlink stream for tel1 in 4250_teal. This is connected to TX1 FTDI UART and has issues.
* moved check to 4250 board ID to start mpu9250s for Teal airframe into fmuv4 rc.board.

 - fixes #10980

    - nuttx in PX4/Firmware (eddfa7421c4ca2eb0969498093e09fa834e920bd): https://github.com/PX4/NuttX/commit/166d898c70141d7ddb179b5ead1c5ea726574411
    - nuttx current upstream: https://github.com/PX4/NuttX/commit/d07a1d459ee9b5b56dbf06a160e8faa4c49fcd10
    - Changes: https://github.com/PX4/NuttX/compare/166d898c70141d7ddb179b5ead1c5ea726574411...d07a1d459ee9b5b56dbf06a160e8faa4c49fcd10

    d07a1d4 2018-12-04 Beat Küng - [REJECTED] arm/include/math.h: remove _PARAMS macro (#42)

* Integrated preliminary ICM20948 support into MPU9250 driver.
Fixed temperature conversion for MPU9250/ICM20948.
* Included missing check for PX4_I2C_OBDEV_MPU9250 in main.cpp.
* Added explicit bus for internal MPU9250 on Pixhawk 2.1 to avoid implicit start
of an externally attached device with wrong orientation.

    - micro-CDR in PX4/Firmware (3888bb163eac5c0adfc18e865ef3fb70d0532de9): https://github.com/eProsima/micro-CDR/commit/d23eda8772ecf846531ee470a81fb1be37802e7b
    - micro-CDR current upstream: https://github.com/eProsima/micro-CDR/commit/8b3546e8848e4c07c16ec55730d3ad1aa94396ab
    - Changes: https://github.com/eProsima/micro-CDR/compare/d23eda8772ecf846531ee470a81fb1be37802e7b...8b3546e8848e4c07c16ec55730d3ad1aa94396ab

 - these flags were accumlating on top of each other anytime cmake had to reconfigure

Necessary because NuttX defines pollfd differend from
the POSIX standard. The difference of field order makes
use of C++ designated initializers to compile for both
platforms impossible.

If the landed state was set before the position controller starts it
would get updated with the first poll_subscriptions() anyways. But it's
not on all posix and nuttx platforms I tested and the deleted statement
just copies the zero message into the struct which is already zero.