can: rcar_canfd: Fix R-Car Gen4 DCFG.DSJW field width

On R-Car Gen4 CAN_FD variants, the Data Bit Rate Resynchronization Jump
Width Control (DSJW) field in the Channel n Data Bitrate Configuration
Register (DCFG) register is one bit wider than on older variants.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/all/c4e8bc220bf87e6c7e375f7a2ce51e2aa89ea8a7.1674499048.git.geert+renesas@glider.be


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