ARM: dts: rockchip: Enable usb PHY on rk3288-evb board

Enable usb PHY for all usb ports on rk3288-evb.

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