MFC r265358, r265427, r265777, r265783,
 r265806, r265872, r266012 and r266394:

- Multiple DWC OTG host mode related fixes, improvements and optimisations.
- Add full support for ISOCHRONOUS transfers to the DWC OTG driver.
- Use the interrupt filter to handle basic USB FIFO interrupts.
- Fixed unbalanced unlock in case of "dwc_otg_init_fifo()" failure.
- Add common spinlock to the USB bus structure.