can: rcar_canfd: Add struct rcanfd_regs variable to struct rcar_canfd_hw_info

R-Car Gen3 and Gen4 have some differences in the register offsets. Add
struct rcanfd_regs variable regs to the struct rcar_canfd_hw_info to
handle these differences.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://patch.msgid.link/20250417054320.14100-16-biju.das.jz@bp.renesas.com


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