Change the return type as void for SoC specific init function as it
always return 0.

Link: https://lore.kernel.org/all/20220710115248.190280-6-biju.das.jz@bp.renesas.comSigned-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>