usb: dwc2: Add support of dedicated full-speed PHY interface

usb: dwc2: Add support of dedicated full-speed PHY interface

Do modifications in dwc2_hsotg_core_init_disconnected() function to
enable USB 1.1 Full-Speed Serial Transceiver Select in GUSBCFG register
if corresponding speed and PHY types are chosen. Adjust device speed
selection in DCFG register as well.

Signed-off-by: Vahram Aharonyan <vahrama@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>