PM / AVS: rockchip-io: add io selectors and supplies for rk3328

This adds the necessary data for handling io voltage domains on the rk3328.
As interesting tidbit, the rk3328 only contains one iodomain area in the
regular General Register Files (GRF).

Signed-off-by: David Wu <david.wu@rock-chips.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>