arm64: dts: rockchip: switch Rock 5C to PMIC-based TSHUT reset

Radxa Rock 5C supports both CRU-based (default) and PMIC-based reset
upon thermal runaway conditions. The former resets the SoC by internally
poking the CRU from TSADC, while the latter power-cycles the whole board
by pulling the PMIC reset line low in case of uncontrolled overheating.

Switch to a PMIC-based reset, as the more 'thorough' of the two.

Tested by temporarily setting rockchip,hw-tshut-temp to 65C to simulate
overheating - this causes the board to reset when any of the on-chip
temperature sensors surpasses the tshut temperature.

Requires Alexander's patch [1] fixing TSADC pinctrl assignment

[1] https://lore.kernel.org/r/20250130053849.4902-1-eagle.alexander923@gmail.com

Signed-off-by: Alexey Charkov <alchark@gmail.com>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Link: https://lore.kernel.org/r/20250204-rock-5c-tshut-v1-1-33301e4eef64@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3588s-rock-5c.dts

@@ -873,6 +873,8 @@ regulator-state-mem {
 };
 
 &tsadc {
+	rockchip,hw-tshut-mode = <1>; /* tshut mode 0:CRU 1:GPIO */
+	rockchip,hw-tshut-polarity = <0>; /* tshut polarity 0:LOW 1:HIGH */
 	status = "okay";
 };