lis3lv02d: DT: add wakeup unit 2 and wakeup threshold

This adds support for the the wakeup threshold and
support for the second wakeup unit to the DT based
setup.

Signed-off-by: Sebastian Reichel <sre@kernel.org>
Reviewed-by: Éric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>