arm64: dts: exynos: gs101: add syscon-poweroff and syscon-reboot nodes

arm64: dts: exynos: gs101: add syscon-poweroff and syscon-reboot nodes

Reboot of gs101 SoC can be handled by setting the
bit(SWRESET_SYSTEM[1]) of SYSTEM_CONFIGURATION register(PMU + 0x3a00).

Poweroff of gs101 SoC can be handled by setting bit(DATA[8]) of
PAD_CTRL_PWR_HOLD register (PMU + 0x3e9c).

Tested using "reboot" and "poweroff -p" commands.

Tested-by: Will McVicker <willmcvicker@google.com>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Will McVicker <willmcvicker@google.com>
Link: https://lore.kernel.org/r/20240628223506.1237523-3-peter.griffin@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>