lis3lv02d: send sync event

Send input_sync after each measurement round. This helps userspace to
detect which reported values belongs to the same measurement.

Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Tested-by: Éric Piel <eric.piel@tremplin-utc.net>
Acked-by: Éric Piel <eric.piel@tremplin-utc.net>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>