Documentation: bindings: add dt documentation for Rockchip usb PHY

This patch adds a binding that describes the Rockchip usb PHYs
found on Rockchip SoCs usb interface.

Signed-off-by: Yunzhi Li <lyz@rock-chips.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
1 file changed