dt-bindings: can: fsl,flexcan: add imx93 compatible

Add a new compatible string for imx93.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/all/1669116752-4260-2-git-send-email-haibo.chen@nxp.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>