phy: rockchip-usb: add compatible values for rk3066a and rk3188

We need custom handling for these two socs in the driver shortly,
so add the necessary compatible values to binding and driver.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>