Add rockchip,usbgrf property to support the registers of usb-phy
that are distributed in grf and usbgrf on some special Rockchip
SoCs (e.g RV1108).
Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>