usb: xhci: tegra: Prepare for adding runtime PM support

When adding runtime PM support to the Tegra XHCI driver, it is desirable
to move the function calls to enable the clocks, regulators and PHY from
the tegra_xusb_probe into the runtime PM handlers. Currently, the
clocks, regulators and PHY are all enabled before we call
usb_create_hcd() in tegra_xusb_probe(), however, we cannot call
pm_runtime_get_sync() at this point because the platform device data is
not yet initialised. Fortunately, the function usb_create_hcd() can be
called before we enable the clocks, regulators and PHY and so prepare
for adding runtime PM support, by moving the call to usb_create_hcd()
before we enable the hardware.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>