regulator: rk808: Add RK809 and RK817 support.

    Add support for the rk809 and rk817 regulator driver.
    Their specifications are as follows：
    1. The RK809 and RK809 consist of 5 DCDCs, 9 LDOs
       and have the same registers for these components except dcdc5.
    2. The dcdc5 is a boost dcdc for RK817 and is a buck for RK809.
    3. The RK817 has one switch but The Rk809 has two.

    The output voltages are configurable and are meant to supply power
    to the main processor and other components.

Signed-off-by: Tony Xie <tony.xie@rock-chips.com>
Acked-by: Mark Brown <broonie@kernel.org>
[rebased on top of 5.2-rc1]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>