thermal/drivers/renesas/rzg3s: Add thermal driver for the Renesas RZ/G3S SoC

thermal/drivers/renesas/rzg3s: Add thermal driver for the Renesas RZ/G3S SoC

The Renesas RZ/G3S SoC features a Thermal Sensor Unit (TSU) that reports
the junction temperature. The temperature is reported through a dedicated
ADC channel. Add a driver for the Renesas RZ/G3S TSU.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20250810122125.792966-3-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>