arm64: dts: renesas: sparrow-hawk: Update thermal trip points

arm64: dts: renesas: sparrow-hawk: Update thermal trip points

Since the Sparrow Hawk has a smaller PCB than the White Hawk, it tends
to generate more heat. To prevent potential damage to the board, adjust
the temperature trip points.

Add four "passive" trip points which increasingly throttle the CPU to
prevent overheating. The first trip point at 68°C disables the 1.8 GHz
and 1.7 GHz modes and limits the CPU to 1.5 GHz frequency. The second
trip point at 72°C disables the 1.5 GHz mode and limits the CPU to 1.0
GHz frequency. The third trip point at 76°C uses thermal-idle to start
inserting idle cycles into the CPU instruction stream to cool the CPU
cores down. The fourth and last trip point at 80°C disables the 1.0 GHz
mode and limits the CPU to 500 MHz frequency.

In case the SoC heats up further, in case either of the thermal sensors
readings passes the 100°C, a thermal shutdown is triggered to prevent
any damage to the hardware.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Link: https://lore.kernel.org/20250814233529.191874-1-marek.vasut+renesas@mailbox.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>