dt-bindings: can: sja1000: Convert to json-schema

Convert the NXP SJA1000 CAN Controller Device Tree binding
documentation to json-schema.

Update the example to match reality.

Link: https://lore.kernel.org/all/20220710115248.190280-2-biju.das.jz@bp.renesas.com


Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>