dt-bindings: phy: convert phy-rockchip-inno-usb2 bindings to yaml

Current dts files for Rockchip with 'usb2-phy' subnodes
are manually verified. In order to automate this process
phy-rockchip-inno-usb2.txt has to be converted to yaml.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>