d/patches: ARM: CANOPi: Enable STN2120 OBD controller on UART5

Task https://phabricator.apertis.org/T8966

On the Eclipse KUKSA CANOPi board, the UART5 communicates with the
STN2120 OBD controller. Add the device tree node.

Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>