Merge pull request #1640 from mhkabir/timesync_en

src/modules/mavlink/mavlink_receiver.cpp

src/modules/mavlink/mavlink_receiver.h

src/modules/sdlog2/sdlog2.c

src/modules/sdlog2/sdlog2_messages.h

src/modules/uORB/objects_common.cpp

src/modules/uORB/topics/time_offset.h