Allow use of internal FS PHY on OTG_HS interface
Allow use of internal FS PHY on OTG_HS interface

Some ST parts (like STM32F74xxx / STM32F75xxx) allow the USB_OTG_HS core to be used with
either an external high-speed ULPI PHY or an internal full-speed-only (12mbps) PHY. Currently
the code assumes than an ULPI PHY is used unless the chip has an internal high-speed PHY
(`#if defined(USB_HS_PHYC)`), with no provision to use the internal FS PHY.

hathach/tinyusb,hathach/tinyusb,hathach/tinyusb