can: rcar_canfd: Return early in rcar_canfd_set_bittiming() when not FD

Return early after completing all setup for non-FD mode in
rcar_canfd_set_bittiming(), to prepare for the advent of more FD-only
setup.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://patch.msgid.link/35fcdcad026cfdd0fd361637f065842d99a6c19d.1749655315.git.geert+renesas@glider.be


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