PM / AVS: rockchip-io: add io selectors and supplies for rk3399

This adds the necessary data for handling io voltage domains on the rk3399.
As interesting tidbit, the rk3399 contains two separate iodomain areas.
One in the regular General Register Files (GRF) and one in PMUGRF in the
pmu power domain.

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