can: rcar_canfd: Add helper variable dev

rcar_canfd_channel_probe() and rcar_canfd_probe() have many users of
"pdev->dev".  Introduce shorthands to simplify the code.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/all/2965edc7992ab54dc6c862910775f3466fca6b29.1674499048.git.geert+renesas@glider.be


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>