can: rcar_canfd: Add rcar_canfd_setrnc()

Add rcar_canfd_setrnc() to replace the macro RCANFD_GAFLCFG_SETRNC.
While at it, replace int->unsigned int for local variables offset, page
and num_rules in rcar_canfd_configure_afl_rules().

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://patch.msgid.link/20250417054320.14100-8-biju.das.jz@bp.renesas.com


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