rockchip: io-domain: Add support for RK3328

Port the RK3328 part of the Rockchip IO-domain driver from linux.

This differs from linux version in that pmu io iodomain bit is enabled
in the write ops instead of in an init ops as in linux, this way we can
avoid keeping a full state of all supply that have been configured.

Enable by default on all RK3328 boards, skip rk3328-evb because this
target is typically also used on miscellaneous boards and boxes not
fully supported by U-Boot.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>