arm64: dts: rockchip: force PMIC reset behavior to restart PMU on RK3588 Tiger

arm64: dts: rockchip: force PMIC reset behavior to restart PMU on RK3588 Tiger

The bootloader for RK3588 Tiger currently forces the PMIC reset behavior
(stored in RST_FUN bitfield in register SYS_CFG3 of the PMIC) to 0b1X
which is incorrect for our devices.

It is required to restart the PMU as otherwise the companion
microcontroller cannot detect the PMIC (and by extension the full
product and main SoC) being rebooted which is an issue as that is used
to reset a few things like the PWM beeper and watchdogs.

Let's add the new rockchip,reset-mode property to make sure the PMIC
reset behavior is the expected one.

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Link: https://lore.kernel.org/r/20250627-rk8xx-rst-fun-v4-5-ce05d041b45f@cherry.de
Signed-off-by: Heiko Stuebner <heiko@sntech.de>