clk: actions: Add Actions S500 SoC Reset Management Unit support

Add Reset Management Unit (RMU) support for Actions Semi S500 SoC.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/3fba2e6f0edfac97cb8c6ce60f95c24852578eac.1593788312.git.cristian.ciocaltea@gmail.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>