arm64: defconfig: Enable Renesas MTU3a counter config

Enable MFD & counter related configs for Renesas MTU3a Counter as
it is populated on RZ/{G2L, LC, UL} and RZ/V2L SMARC EVKs.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230417100607.309068-1-biju.das.jz@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>