avoids multiple declarations of...

Both succeed under Posix & NuttX (Pixracer)

This adds two uORB API calls:
- orb_advertise_queue
- orb_advertise_multi_queue

Both add a queue_size parameter to define a maximum number of buffered
item. The existing orb calls use all a queue size of one and thus their
behavior is unchanged. If a writer publishes too fast, the oldest elements
from the queue are silently dropped.
The returned timestamp is always the one from the latest message in the
queue.

Queue size can be set via ioctl during advertisement phase. After that it
cannot be changed anymore.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

Added missing stub function and added SDK 2 and 3 support.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

The inc and lib directories were renamed to incs and libs.

This requires an updated cmake_hexagon and come changes to qurt paths in
PX4.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

The overflow of the uint32_t lead to the land_detector start getting
aborted.

I prefer this way because I think it's more readable.

This brings MPU9250 mag support with the correct scaling in place.

We need to start the external mag before we start the internal mag on
the MPU9250 because the ekf2 does not support voting for the sensor with
the highest priority (or failures) yet, so it will just subscribe to
whatever is at 0.