arch/arm: meson: sm: introduce power domain functions

This commit adds functions to manage secure power domain for
Amlogic SoC's using smc functionality.

Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230531093156.29240-2-avromanov@sberdevices.ru


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