dt-bindings: phy: tegra-xusb: List PLL power supplies

These power supplies provide power for various PLLs that are set up and
driven by the XUSB pad controller. These power supplies were previously
improperly added to the PCIe and XUSB controllers, but depending on the
driver probe order, power to the PLLs will not be supplied soon enough
and cause initialization to fail.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>