dt-bindings: power: add Amlogic A5 power domains

Add devicetree binding document and related header file for
Amlogic A5 secure power domains.

Signed-off-by: Hongyu Chen <hongyu.chen1@amlogic.com>
Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240627-a5_secpower-v1-1-1f47dde1270c@amlogic.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>