usb: dwc3: pci: remove registration of NOP PHYs

None of the PCI platforms need the NOP transceivers, and
since we can now live without the PHYs, removing
registration of the platform devices for them.

Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>