Beat Küng b6b935026a mavlink: switch back from _mavlink_timesync.sync_stamp to hrt_absolute_time
- the timestamp is only used for logging and log analysis. For that it's
  important to have the timestamp when a setpoint becomes active.
- there was a consistent problem with the position_setpoint_triplet
  timestamp, where the timestamp was just bogus. Timesync seems to work
  correctly though. Might be a problem on the sender side?
  For example here:
  https://logs.px4.io/plot_app?log=41918a7d-4c1d-464d-9abe-aef2c0818d92
2018-08-22 08:31:37 +02:00
..
2018-02-10 20:37:47 -05:00
2018-06-30 19:55:08 -04:00
2018-06-30 19:55:08 -04:00