thermal: renesas: rzg3e: make reset optional

thermal: renesas: rzg3e: make reset optional

The Renesas RZ/T2H (R9A09G077) and RZ/N2H (R9A09G087) SoCs do not have a
reset line.

Prepare for them by making it optional.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: John Madieu <john.madieu.xa@bp.renesas.com>
Tested-by: John Madieu <john.madieu.xa@bp.renesas.com>
Signed-off-by: Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
Link: https://patch.msgid.link/20260108195223.193531-2-cosmin-gabriel.tanislav.xa@renesas.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>