dt-bindings: power: Add Support for Allwinner A733 PCK600 Power Domain Controller

The A733 PCK600, similar to A523 PCK600, is likely a customized version
of ARM PCK-600 power controller. They share the same BSP drivers in the
package provided by Radxa, with the only difference being the lack of
resets.

Therefore, document A733 compatible and make resets required only for
the other models, as well as prepare the PD definitions for future
device trees.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Yuanshen Cao <alex.caoys@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>