phy: rockchip-inno-usb2: add a new driver for Rockchip usb2phy

The newer SoCs (rk3366, rk3399) take a different usb-phy IP block
than rk3288 and before, and most of phy-related registers are also
different from the past, so a new phy driver is required necessarily.

Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
Suggested-by: Heiko Stuebner <heiko@sntech.de>
Suggested-by: Guenter Roeck <linux@roeck-us.net>
Suggested-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>