dt-bindings: phy: Add DT bindings for Xilinx ZynqMP PSGTR PHY

dt-bindings: phy: Add DT bindings for Xilinx ZynqMP PSGTR PHY

Add DT bindings for the Xilinx ZynqMP PHY. ZynqMP SoCs have a High Speed
Processing System Gigabit Transceiver which provides PHY capabilities to
USB, SATA, PCIE, Display Port and Ehernet SGMII controllers.

Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200629120054.29338-2-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>