rockchip: dts: rk3368-lion: add /chosen/tick-timer

To support bootstage recording, we want to mark our DM timer as the
tick-timer; this triggers the support for 'trying harder' to read the
timer in the Rockchip DM timer driver, even if the device model isn't
ready yet.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>