ARM: dts: rockchip: add rk3288 usb PHY

This patch adds a device_node for RK3288 SoC usb phy. It also
defines the phy to be used by three usb controllers: usb_host0/1
and usb_otg.

Signed-off-by: Yunzhi Li <lyz@rock-chips.com>
Tested-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>