usb: dwc3: add ULPI interface support

Registers DWC3's ULPI interface with the ULPI bus when it's
available.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --cc drivers/usb/dwc3/Kconfig
Simple merge

diff --cc drivers/usb/dwc3/Makefile
Simple merge

diff --cc drivers/usb/dwc3/core.c
Simple merge

diff --cc drivers/usb/dwc3/core.h
Simple merge

diff --cc drivers/usb/dwc3/ulpi.c
Simple merge