arm64: dts: meson: fix S4 power-controller node

The power-controller module works well by adding its parent
node secure-monitor.

Fixes: 085f7a29 ("arm64: dts: add support for S4 power domain controller")
Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240412-fix-secpwr-s4-v2-1-3802fd936d77@amlogic.com


Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>