dt-bindings: USB: Add bindings for Ingenic JZ4775 and X2000.

Move Ingenic USB PHY bindings from Documentation/devicetree/bindings/usb
to Documentation/devicetree/bindings/phy, and add bindings for JZ4775 SoC
and X2000 SoC.

Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20201116141906.11758-3-zhouyanjie@wanyeetech.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>