Since commit

| 1f923440 ("dt-bindings: can: add can-controller.yaml")

there is a common CAN controller binding. Add this to the sun4i_can
binding.

Link: https://lore.kernel.org/all/20220124220653.3477172-3-mkl@pengutronix.de
Cc: Evgeny Boger <boger@wirenboard.com>
Cc: Gerhard Bertelsmann <info@gerhard-bertelsmann.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>